Furosemide Research Articles

Preparation and Physical Properties of Quaternary Mn2FeSi0.5Al0.5 Alloy Powders with Heusler and β-Mn Structures

Manganese-based alloys with the composition Mn2FeZ (Z = Si, Al) have been extensively investigated in recent years due to their potential applications in spintronics. The Mn2FeSi alloy, prepared in the form of ingots, powders, or ribbons, exhibits either a cubic full-Heusler (L21) structure, an inverse-Heusler (XA) structure, or a combination of both. In contrast, the Mn2FeAl alloy has so far been synthesized only in the form of ingots, featuring a primitive cubic (β-Mn type) structure. This study focuses on the new quaternary Mn2FeSi0.5Al0.5 alloy synthesized from pure Mn, Fe, Si, and Al powders via mechanical alloying. The elemental powders were ball-milled for 168 h with a ball-to-powder ratio of 10:1, followed by annealing at 550 °C, 700 °C, and 950 °C for 8 h in an argon protective atmosphere. The results demonstrate that annealing at lower temperatures (550 °C) led to the formation of a Heusler structure with a lattice constant of 0.5739 nm. Annealing at 700 °C resulted in the coexistence of several phases, including the Heusler phase and a newly developed primitive cubic β-Mn structure. Further increasing the annealing temperature to 950 °C completely suppressed the Heusler phase, with the β-Mn structure, having a lattice constant of 0.6281 nm, becoming the dominant phase. These findings confirm the possibility of tuning the structure of Mn2FeSi0.5Al0.5 alloy powder—and thereby its physical properties—by varying the annealing temperature. The sensitivity of magnetic properties to structural changes is demonstrated through magnetization curves and zero-field-cooled/field-cooled curves in the temperature range of 5 K to 300 K.

Drug-Phospholipid Co-Amorphous Formulations: The Role of Preparation Methods and Phospholipid Selection.

Background/Objectives: This study aims to broaden the knowledge on co-amorphous phospholipid systems (CAPSs) by exploring the formation of CAPSs with a broader range of poorly water-soluble drugs, celecoxib (CCX), furosemide (FUR), nilotinib (NIL), and ritonavir (RIT), combined with amphiphilic phospholipids (PLs), including soybean phosphatidylcholine (SPC), hydrogenated phosphatidylcholine (HPC), and mono-acyl phosphatidylcholine (MAPC). Methods: The CAPSs were initially prepared at equimolar drug-to-phospholipid (PL) ratios by mechano-chemical activation-based, melt-based, and solvent-based preparation methods, i.e., ball milling (BM), quench cooling (QC), and solvent evaporation (SE), respectively. The solid state of the product was characterized by X-ray powder diffraction (XRPD), polarized light microscopy (PLM), and differential scanning calorimetry (DSC). The long-term physical stability of the CAPSs was investigated at room temperature under dry conditions (0% RH) and at 75% RH. The dissolution behavior of the CCX CAPS and RIT CAPS was studied. Results: Our findings indicate that SE consistently prepared CAPSs for CCX-PLs, FUR-PLs, and RIT-PLs, whereas the QC method could only form CAPSs for RIT-PLs, CCX-SPC, and CCX-MAPC. In contrast, the BM method failed to produce CAPSs, but all drugs alone could be fully amorphized. While the stability of each drug varied depending on the PLs used, the SE CAPS consistently demonstrated the highest stability by a significant margin. Initially, a 1:1 molar ratio was used for screening all systems, though the optimal molar ratio for drug stability remained uncertain. To address this, various molar ratios were investigated to determine the ratio yielding the highest amorphous drug stability. Our results indicate that all systems remained physically stable at a 1.5:1 ratio and with excess of PL. Furthermore, the CAPS formed by the SE significantly improves the dissolution behavior of CCX and RIT, whereas the PLs provide a slight precipitation inhibition for supersaturated CCX and RIT. Conclusions: These findings support the use of a 1:1 molar ratio in screening processes and suggest that CAPSs can be effectively prepared with relatively high drug loads compared to traditional drug-polymer systems. Furthermore, the study highlights the critical role of drug selection, the preparation method, and the PL type in developing stable and effective CAPSs.

Cycling Stability Based on the Morphological Characteristics of Si-Based Anode Materials for Sulfide-Based All Solid-State Batteries

Sulfide-based all-solid-state batteries (ASSBs) have emerged as promising next-generation energy storage devices due to their high safety and energy density. Si, with its high theoretical capacity (3579 mAh g-1 for Li3.75Si), is a promising anode material for ASSBs. However, its large volume change (~300%) during cycling remains a significant challenge. Recent studies have shown excellent performance of micron-sized pure Si in sulfide-based ASSBs, but inconsistent cycle life characteristics complicate understanding of Si anode degradation mechanisms. To address this, nanolayer Si-coated graphite (Si/Gr) composites have been proposed, but their performance and degradation mechanisms in sulfide-based ASSBs remain unclear.This study investigates the impact of Si morphological characteristics on the cycle stability of sulfide-based ASSBs and compares the degradation mechanisms of Si/Gr and pure Si composite anodes. Half-cells were fabricated using Si/Gr composites (~10 μm spherical particles, ~50 nm Si coating) and pure Si (1-5 μm). Cycle performance was evaluated for 50 cycles. Microstructural and chemical changes were analyzed using m-XRD, SEM/EDS, XPS, and TEM/EDS/EELS.The initial capacity of Si/Gr was about 820 mAh g-1, which was higher than that of pure Gr(340 mAh g-1), but after 50 cycles, the cycle retention was 82%, which was faster than that of pure Gr(97%). Pure Si, on the other hand, showed a sharp decrease in capacity to nearly 0% in 10 cycles. The faster degradation of Si/Gr compared to pure Gr was attributed to interactions between Si and Gr within the composite, which had a greater impact than interfacial reactions with the solid electrolyte. Specifically, the Si coating gradually reduced Gr crystallinity during cycling, diminishing lithium storage capacity. For pure Si, crack formation at the Si/SE interface and excessive SEI formation during delithiation led to rapid capacity loss. In conclusion, Si/Gr offered higher capacity than Gr but degraded faster, while the thin Si coating had local volume changes better than micron-sized Si, resulting in higher capacity and improved cycle life.This research elucidates the degradation mechanisms of Si-C composites in sulfide-based ASSBs and provides insights for optimizing Si-based anodes. These findings offer valuable guidance for developing high-performance sulfide-based ASSBs with enhanced long-term reliability.

Anode Properties of Si-Based Composite Electrodes Containing Two Silicides with Different Functions for Lithium-Ion Batteries

A LaSi2/Si composite electrode has longer charge-discharge cycle life than a pure Si electrode. However, the capacity of the composite electrode decreases gradually over repeated cycles. We identified the microstructure of the electrode to ascertain factor of capacity fading by transmission electron microscopy. Before cycling, the pure Si phase was highly dispersed in the LaSi2 matrix phase. In such microstructure, the elastic LaSi2 could alleviate the stress caused by Si volume change during lithiation and delithiation; and hence it suppressed electrode disintegration.1 On the other hand, prior to capacity decline, the positions of LaSi2 and pure Si were reversed. The LaSi2 phase was surrounded by the pure Si matrix phase and the LaSi2 could not relax the stress. Hence, we added stiff silicide which withstands the Si-generated stress into the LaSi2/Si. As a result, the LaSi2/NbSi2/Si exhibited superior cycle life. Herein, we investigated the effect of difference in elastic silicides on cycle life. The MSi2/CrSi2/Si (M = Ni, La, or Sm) powder was prepared by mechanical alloying method. The composite powder was deposited on the Cu substrate using a gas-deposition (GD) method. The fabricated GD electrode was mounted in a 2032-type coin-cell as the working electrode. Li metal foil and glass fiber filter were also used as the counter electrode and separator, respectively. In addition, we used 1 mol dm–3 lithium bis(fluorosulfonyl)amide dissolved in N-methyl-N-propylpyrrolidinium bis(fluorosulfonyl)amide as an ionic liquid electrolyte. We conducted galvanostatic charge-discharge tests in constant current mode with a charge capacity limitation of 1000 mA h g(Si)–1. In the present study, we did not consider the capacity of the silicides: the Si-alone and silicide-alone electrodes stored Li, while the silicide in the silicide/Si electrodes did not show the reversible capacity2. Figure 1 shows the cycle life of the MSi2/CrSi2/Si electrodes with the different indentation work rates of MSi2. The indentation work rate means an indicator of elasticity: it indicates that how much the MSi2 layer returns to its original shape after deformation. The cycle life was the shortest when NiSi2 with the lowest indentation work rate was used. In contrast, when SmSi2 was used, it achieved the longest cycle life with high reversible capacity of 1000 mA h g(Si)–1 over 1900 cycles. We predicted that the cycle life improved using a more elastic silicide. However, the cycle life adversely lowered when LaSi2 with the highest elasticity was used. Thus, the excellent performance should be achieved based on the synergistic effects of stiff and elastic silicides.1) Y. Domi, H. Usui, K. Nishikawa, and H. Sakaguchi, ACS Appl. Nano Mater., 4, 8473 (2021).2) Y. Domi, H. Usui, K. Nishikawa, H. Sakaguchi, et al., Electrochemistry, 88, 548 (2020). Figure 1

Advanced SiGe:B Raised Sources and Drains for p-type FD-SOI MOSFETs

We have evaluated the feasability of selectively growing (at 600°C-700°C, 20 Torr and with a SiH2Cl2 + GeH4 + B2H6 + HCl chemistry) SiGe:B Raised Sources and Drains on each side of PMOS FD-SOI devices with a vertical Ge concentration gradient. The reason was twofold : (i) inject meaningful amounts of uniaxial compressive strain and boost hole mobility thanks to really high Ge concentrations (50%) in layers on each side of the channel and (ii) benefit from SiGe:B 20% to 30% layers on top, that are easier to germano-salicide, for instance with Ni or NiPt. As the diborane flow increased, we had, whatever the Ge concentration (20%, 30% or 50%), (i) sub-linear SiGe:B growth rate increases (from +14% up to + 23%) and (ii) linear decreases of the “apparent” Ge concentration from X-Ray Diffraction (XRD), as shown in Figures 1a and 1b. They were due to (i) a catalysis of H/Cl desorption by B adatoms and (ii) compressive strain compensation by small size B atoms, respectively. The resulting substitutional B concentrations increased almost linearly with the B2H6 mass-flow. The slopes of those increases were steeper and B concentrations systematically higher for higher Ge contents, however (at most 2.2x1020 cm-3 for 50% of Ge), as illustrated in Figure 1c. We otherwise showed, for Si0.7Ge0.3:B layers, that the Ge atomic concentration was steady as the B2H6 mass-flow increased. Atomic, substitutional and ionized B concentrations (from Secondary Ions Mass Spectrometry, XRD and Hall effect measurements) were the same for the lowest diborane flow probed (e.g. 7x1019 cm-3). For a medium flow, atomic and substitutional B concentrations were equal (e.g. 1.4x1020 cm-3), while the ionized B concentration was ~80% of it. Discrepancies were the highest for the highest diborane flow probed, with substitutional and ionized B concentrations ~80% and ~60% the atomic B concentration of 2.3x1020 cm-3, then (Figure 1d). The specifics of SiGe:B Selective Epitaxial Growth (SEG) in sources and drains regions on each side of FD-SOI devices (Figure 2) were then described, such as (i) loading effects, because of the presence of dielectrics, resulting in significant growth rate increases (x1.5 - x1.7), together with slight Ge and B concentrations increases that might impact the layer quality on patterned wafers, (ii) facet formation, (iii) the importance of proper surface preparation prior to epitaxy and of tight SiN hard masks on top of poly-Si gates, (iv) the strain loss happening upon germano-salicidation and so on. Growing a thin Si(:B) cap on SiGe:B is another way of obtaining uniform and stable metallic contacts. This is why we have studied the capping, with pure Si, of SiGe 20% or 30% layers. As growth had to be conducted, for the SEG of Si with a chlorinated chemistry, at temperatures significantly higher than that of SiGe (750°C, typically, to be compared with 700°C for SiGe 20% and 650°C only for SiGe 30%), we have quantified the impact of using temperature ramping-ups with SiH2Cl2 + HCl flowing into the growing chamber. The purpose of such active ramps was to avoid elastic strain relaxation, e.g. the formation of SiGe surface undulations that would happen with temperature ramping-ups under H2 only. Superior quality 2D SiGe / Si stacks were then obtained, as shown by X-Ray Reflectivity and XRD. Energy Dispersive X-ray maps of such stacks enabled us to quantify loading effects on patterned wafers. SiGe growth rates in small, recessed windows were 1.5 times (SiGe 30%) – 1.8 times higher (SiGe 20%) than on bulk, blanket Si. Meanwhile, Ge concentrations were 2% to 3% higher. Finally, Si growth rates were lower than bulk, most probably because of the presence of thick buried oxide layers on those patterned wafers that impacted the effective surface temperature during growth. Figure 1

An Assessment of the Lateral Selective Etching, with HCl, of High Versus Low Ge Content SiGe Layers

We have evaluated the feasibility of performing, with gaseous HCl, a lateral selective etching of high versus low Ge content SiGe layers. Such a know-how might be useful to fabricate, besides Complementary Field Effect Transistors, other types of devices relying on stacked nanosheets and multiple selective etchings such as 3D Resistive or Oxyde Random Access Memories (for In-Memory Computing).To that end, we have grown {20 to 25 nm thick Si / ~ 12-15 nm thick Si0.8Ge0.2 or Si0.75Ge0.25 / ~ 11-14 nm thick Si0.5Ge0.5} multilayers on SOI substrates. After a low temperature capping with SiN, such stacks were patterned into regular arrays of square mesas or lines with a stop on the buried oxide, to laterally have access to the layers of interest. The temperature used, in our 300 mm Reduced Pressure - Chemical Vapor Deposition chamber, to grow such stacks was 550°C. Meanwhile, the in-situ HCl etch temperature was always 500°C. The aim of such low process temperatures was to minimize the thermal budget multilayers were submitted to, in order to minimize elastic relaxation and avoid plastic relaxation while still having reasonable growth and etch rates. The overall compressive strain was indeed high in such stacks given the number, individual thicknesses and Ge concentrations of SiGe layers. Multilayers grown at 550°C, 20 Torr with (i) a SiH2Cl2 + GeH4 chemistry for Si0.5Ge0.5, (ii) a Si2H6 +GeH4 chemistry for Si0.75Ge0.25 or Si0.8Ge0.2 and (iii) pure Si2H6 for Si were in some places defective, with the presence on the surface of islands. Such defects were likely due to Si2H6 mass-flows which were too large, resulting in gas phase nucleation and, in some places, the formation of defects that increased in size as growth happened. We thus proceeded differently. Instead of Si2H6 + GeH4, we have used a SiH4 + GeH4 chemistry for the epitaxy of SiGe 20% or 25% layers. We succeeded in having reasonable SiGe 20% and 25% growth rates at 550°C, 20 Torr, which was not a given with that chemistry. We also showed that a x/(1-x) = 2.81*F(GeH4)/F(SiH4) relationship perfectly accounted for the almost linear increase of the Ge concentration x with the F(GeH4)/F(SiH4) mass-flow ratio. We otherwise reduced the Si2H6 mass-flow and added HCl to minimize gas phase nucleation and suppress the formation of amorphous inclusions in the Si layers. The linear dependency of the 550°C, 20 Torr Si growth rate on the Si2H6 and HCl mass-flows was modelled with the following phenomenological relationship: Si Growth Rate (nm min.-1) = 3260*F(Si2H6)/F(H2) – 1070*F(HCl)/F(H2).We then determined, at 500°C, 600 Torr, the (001) blanket HCl etch rates of SiGe 30% and 40%: 1.37 and 5.28 nm min.-1. Based on such data, we should have the following SiGe 50%, 25% and 20% etch rates: 20.0, 0.70 and 0.36 nm min.-1, respectively. Meanwhile, the pure Si etch rate should be negligible: 0.025 nm min.-1 only. Should we then define theoretical selectivities as being ratios between (i) SiGe 50% and (ii) SiGe 25%, SiGe 20% or pure Si blanket (001) etch rates, we would obtain promising selectivities (29, 56 and 800) when laterally etching of SiGe 50% versus SiGe 25% SiGe 20% and Si.We then switched over to patterned wafers. The lateral selective etching of Si0.5Ge0.5 versus Si0.8Ge0.2 (and Si) was feasible. The following features were highlighted: (i) Si0.5Ge0.5 lateral etch rates along the <110> directions were much smaller than in the [001] direction and (ii) because of micro-loading, lateral etch rates were definitely higher for squares than for lines (0.9 - 1.1 nm min.-1 for lines, to be compared with 1.7 – 2.1 nm min.-1 for squares). Meanwhile, the lateral selective etching of Si0.5Ge0.5 versus Si0.75Ge0.25 was far from being perfect, with much higher Si0.5Ge0.5 etch rates and a significant Si0.75Ge0.25 recessing at tunnel entrances (see Figure 1). Si0.75Ge0.25 floors and ceilings were otherwise far more etched and thus tilted than Si0.8Ge0.2 ones. Inserting very thin Si spacers between Si0.5Ge0.5 cores and Si0.75Ge0.25 claddings partly solved those issues, with no recessing and lesser etchings at the entry points of tunnels, then (see Figure 2). Figure 1

Investigating the Degradation Behavior of Silicon Anodes for Lithium-Ion Batteries

Silicon (Si), which delivers higher capacity than that of graphite, is an adequate material for enhancing the energy densities of lithium-ion batteries (LIBs). However, rapid capacity deterioration has made it difficult for practical use and commercialization. Furthermore, there is limited understanding regarding the degradation conditions and mechanisms of Si anode. Thus, our study aims to elucidate the degradation behavior and conditions of Si anodes while exploring the underlying degradation mechanisms.To investigate the degradation conditions of Si anodes, we conducted electrochemical experiments on NCM||Si full cells under various conditions. Cycling under sparse and ample electrolyte conditions was compared. It revealed stable cycling up to 400 cycles under sufficient conditions, while a rapid deterioration was observed after 200 cycles under sparse conditions. Additionally, we compared cycling performance under room temperature and elevated temperature conditions. Unlike conventional graphite-based LIBs, which typically exhibit more unstable cycling at high temperatures than room temperatures, NCM||Si full cells demonstrated more stable cycling behavior at elevated temperatures. While a sharp degradation occurred after approximately 200 cycles at room temperature, high temperatures yielded a remarkable 99.8% Coulombic efficiency and stable cycling beyond 300 cycles. Moreover, cycling performance was compared at low and high C-rates. At low C-rates, lifetimes exceeding 300 cycles were observed, whereas at high C-rates, rapid degradation commenced around 250 cycles. Through degradation condition experiments, we confirmed that Si anodes experience accelerated degradation with sparser electrolytes, lower temperatures, and higher C rates.Conditions of low temperature and high C-rate kinetically limit the movement of electrons and Li ions. Therefore, we hypothesized that the observed degradation behavior of Si may be attributed to restricted kinetics. To investigate this, we conducted Electrochemical impedance spectroscopy (EIS) measurements on Si, Si/Gr composite, and graphite (Gr) anodes across various states of charge (SOC). Our findings revealed pronounced differences in resistance behavior among these materials throughout the lithiation process. While graphite exhibited a linear resistance increase with lithiation, the Si/Gr composite maintained low resistance. However, pure Si anodes exhibited low resistance up to SOC60 but sharply increased resistance, quadrupling at SOC80. This observation suggests that Si encounters a significant kinetic barrier at high SOC ranges, which likely serves as a primary trigger for degradation.To enhance our comprehension of the degradation mechanism, we examined electrode surfaces post-cycling through scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). In the degraded Si electrode after 200 cycles, we observed pits scattered throughout the electrode surface which appeared to result from repeated expansion and contraction cycles. Furthermore, through EDS image analysis, we noted a significant increase in F peak content in areas where the Si peak had decreased. These observations suggest a correlation between the degradation of Si electrodes and an increase in side-reaction with electrolytes.It is known that Si undergoes a structural transformation from amorphous to crystalline, forming an over-lithiated structure, within a voltage range of less than 50 mV. Unlike graphite, which undergoes lithiation by intercalation, Si undergoes lithiation by chemical transformation, resulting in different products depending on the operating voltage. Therefore, understanding the actual driving voltage range of Si anodes is crucial for deducing the products of Si during charging and discharging. Thus, we conducted a three-electrode experiment in NCM||Si full cells. During the charging and discharging, the actual operating voltage of the Si electrode was observed to range from 0.031V to 2V. Similarly, in NCM||SiGr full cells, the actual operating voltage of the SiGr electrode ranged from 0.073V to 0.85V. Given that charging and discharging of the Si electrode occur even below 50mV, it suggests the presence of overcharged crystalline Si.To confirm the existence of this crystalline Si, we additionally conducted X-ray diffraction (XRD) and dQ/dV analysis. XRD analysis of degraded electrodes exhibited that as the cycle increased, indicating accelerated degradation, the peak of crystalline Si increased. The trend of increasing crystalline peak with progressing degradation was also confirmed through dQ/dV analysis.In conclusion, We observed the degradation behavior on Si electrodes and confirmed that the generation of over-lithiated crystalline Si is the main degradation cause. This discovery is expected to contribute to the future development of Si-based LIBs by providing valuable insights into achieving long cycles of Si anodes.

(Invited) Epitaxial Process Development and Challenges for Advanced SiGe BiCMOS

Silicon Germanium (SiGe) Heterojunction Bipolar Transistors (HBTs) are used daily, mainly in the communication field. Their co-integration with Complementary Metal Oxide Semiconductor (CMOS) technology, i.e. BiCMOS, enables versatile microchips that combine analog, radio-frequency and digital functions. Applications that drive the development of BiCMOS technologies today are Low Earth Orbit (LEO) satellite communications, for which the minimum noise figure of SiGe HBT (NFMIN) between 10 and 30 GHz is one of the most critical figures of merit on the receiver side. It is expected that BiCMOS will play a significant role in the 6G infrastructure, in particular for communications in the D-band spectrum (110-170 GHz), for which the challenge at HBT level is to demonstrate maximum oscillation frequency fMAX > 500 GHz.Benefitting from mature CMOS technologies, the smallest CMOS node used in BiCMOS chips is the 45 nm partially depleted silicon on insulator [1]. STMicroelectronics has been using the 55 nm node since 2014 [2]. These nodes are today sufficient to address the digital content of the targeted circuits, while offering the right performance/cost trade-off. Although the HBT performance depends on lateral scaling too, it is mainly driven by the 1D dopant profile. Multiple Si and SiGe layers are grown by Reduced Pressure-Chemical Vapor Deposition (RP-CVD) epitaxy, defining the core of the device. For a self-aligned architecture such as STMicroelectronics’ EXBIC architecture, four epitaxy steps with different doping levels are required (Fig. 1) [3]. Improvement of key electrical parameters such as NFMIN and fMAX depends on the optimization of these epitaxies.Specifically, the collector epitaxy can be performed by non-selective or selective epitaxy, each with its advantages and drawbacks. Non-selective epitaxy is performed early in the BiCMOS process flow, with no thermal budget impact on the CMOS process. This kind of epitaxy is also cheaper but can cause auto-doping at the epitaxial interface [4] and put constraints on the collector integration, that are solved by the selective epitaxy of the collector. This scheme is used in the latest devices from both STMicroelectronics [3] and GlobalFoundries [5].The transit time of electrons through the base is determined by its thickness and its composition. Significant performance gains have been achieved by switching from pure Si to a graded SiGe base architecture. The bandgap variation due to the graded SiGe composition creates a pseudo-electric field that accelerates the minority carriers transport through the base and limits electron-hole recombination. The addition of carbon into the base limits the boron diffusion and reduces the base thickness, further improving performance. However, only substitutional carbon atoms are required while interstitial carbon atoms must be avoided. The amount of carbon, incorporated in fully substitutional sites, is controlled by the silicon precursor used during RP-CVD epitaxy. At a given temperature it has been shown that a more reactive silicon precursor allows for better substitutional carbon incorporation. By switching from SiH2Cl2 (DCS) to SiH4, the amount of substitutional carbon atoms was increased by 250 % [6]. Following this idea, Si2H6 has been introduced as a silicon precursor to achieve even better substitutional carbon incorporation due to its higher reactivity [7].The emitter process is usually performed by non-selective Si:As epitaxy. This type of epitaxy produces polycrystalline Si:As with a monocrystalline Si:As core above the crystalline base. The emitter resistance can be reduced by processing a fully monocrystalline emitter. A possible solution involving low temperature deposition and solid phase epitaxial regrowth is proposed [8].An overview of the existing problems for each epitaxy step will be given, outlining potential solutions to increase HBT performance to meet customer requirements.[1] J. Pekarik et al., IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium (BCICTS), 1-4 (2021)[2] P. Chevalier et al., IEEE International Electron Devices Meeting (IEDM),77-79 (2014)[3] A. Gauthier et al., IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium (BCICTS), 187-190 (2023).[4] P. Jerier and D. Dutartre, J. Electrochem. Soc. 146 ,331 (1999)[5] J. Pekarik et al., ECS Transactions, 109, 141 (2022)[6] F. Brossard et al., International SiGe Technology and Device Meeting (ISTDM), 1-2 (2006)[7] J. Vives et al., ECS Transactions, 109 (4), 237-248 (2022)[8] F. Deprat et al., ECS Transactions, 109, 159 (2022) Figure 1

Nucleation and Growth Mechanisms of Polycrystalline Sige-Based Materials By Chemical Vapor Deposition at Reduced Pressure

Polycrystalline Si and SiGe-based materials deposited on dielectrics have a wide range of key applications, like as gate materials for complementary metal oxide semiconductor (CMOS) devices [1-2], as active layers in thin film transistors (TFTs) [3] and as dopant diffusion sources to form ultra-shallow elevated junctions [4]. The control of the Si or SiGe nucleation on dielectric surfaces is also a key towards selective epitaxy at low growth temperature. At these low growth temperatures, the standard selective process, where the precursors and the etching gas are injected together, was replaced by Cyclic Deposition Etch (CDE) processes [5]. It generally consists of the repetition of two steps: A non-selective deposition with epitaxial growth on Si regions and amorphous/polycrystalline deposition on dielectric regions. This is followed by an in-situ Cl-based etching, usually with HCl. Such CDE processes would benefit from having the lowest deposition rate on the dielectrics with respect to the epilayer. The determination of key parameters that characterize the nucleation process on dielectric surfaces, such as incubation time, nucleation rate, coalescence point, and the final resulting microstructure is therefore beneficial to optimize the deposition/etch cycles. Pure Si deposition on dielectric surfaces was widely studied in various CVD reactors, but the nucleation and growth mechanisms of SiGe-based materials has not been studied as extensively.The SiGe nucleation was investigated in a Reduced-pressure-Chemical Vapor Deposition (RP-CVD) reactor at 550 °C, 10 Torr, on blanket Si wafers covered with 10 nm of thermally grown SiO2 using either a SiH4 or Si2H6-based chemistry with GeH4. Using Si2H6, SiGe polycrystalline films were obtained even for low deposition times, in contrast with the use of SiH4, which led to a progressive increase in both density and size of the SiGe nuclei. This may be due to the higher reactivity of the Si2H6 precursor compared to the SiH4. The weaker Si-Si bonds than Si-H bonds resulted in easier chemical decomposition of the silicon precursor and the formation of hydrogenated Si sub-species (intermediates) with Si2H6 than with SiH4. This may lead to a higher frequency of effective collisions at the surface when using the Si2H6 chemistry, producing an extremely fast saturation of the nuclei density and a favorable growth of the nuclei. Consequently, two different film morphologies were obtained, depending on the type of silicon precursor used. The polycrystalline SiGe deposited using a Si2H6-based chemistry (Fig.1a) exhibited a smoother film (RMS = 1.33 nm) compared to a SiH4-based chemistry (RMS = 21.06 nm) (Fig.1b) and a large grain microstructure with SiH4 (Fig.1d), whereas with Si2H6 (Fig.1c), the microstructure was columnar with small grains.The SiGe nucleation, using SiH4, was compared between 10 nm SiO2 and 10 nm Si3N4 surfaces. Due to the stronger O-H bond than the N-H bond, the Si3N4 surface was found to be more reactive than a SiO2 surface, resulting in significantly faster nucleation kinetics on Si3N4. This led to different microstructures for thicker films (Fig2). AFM and SEM images showed smoother film with a small grain microstructure for films deposited on Si3N4 (RMS = 2.96 nm) (Fig2.b).Finally, the nucleation mechanisms on thermally grown SiO2 were investigated using a SiH4-based chemistry with various GeH4, SiH3CH3 and PH3 flows. The incubation time was not affected by the GeH4 flow with a common inflexion point around 20 s (Fig.3). Increasing the GeH4 flow reduced the nucleation rate (from 7.5x10-2 to 1.1x10-2 cm-2. s-1) and decreased the density of nuclei at saturation (from 4.40x109 to 0.74x109 cm-2). These results highlighted the advantage of high GeH4 flow ratios to achieve selectivity towards SiO2 surfaces.The introduction of SiH3CH3 into the gas mixture, either at small (F(SiH3CH3/F(H2)=8.3x10-6) or large flows (F(SiH3CH3/F(H2)=6.7x10-5), did not affect the nucleation mechanisms. In contrast, the addition of a small amount of PH3 (F(PH3/F(H2)=1.7x10-7) greatly reduced the density of nuclei at saturation and increased the incubation time (from 20 to 41 s) which might be due to the poisoning effect of P adatoms on the surface.This study will help to further understand the SiGe-based polycrystalline growth and optimize the deposition steps for cyclic deposition etch (CDE) approaches, with a detailed investigation of the nucleation and growth mechanisms as a function of precursors, the nature of the dielectric layer and the incorporation of impurities.[1] K.Kistler, in Tech. Dig. of Int. Electron Devices Meet.,p. 727 (1993)[2] V.Z.Z.Q.Li, in Tech. Dig. of Int. Electron Devices Meet.,p. 833 (1997)[3] T..J.King, IEEE Trans. Electron Devices, ED-41, 1581 (1994)[4] D.T.Grider, J. Electron. Mater., 24, 1369 (1995)[5] M.Bauer, US Patent 0234504 A1 (2006) Figure 1

Controlling Nickel Deposition Depth in Mesoporous Silicon through Wetting and Deposition Kinetics

A strong mechanical and electrical connection between silicon (Si) and a metal film, such as nickel (Ni) or copper (Cu), is essential for several fields of application such as microelectronics, MEMS, analytical systems, biomedical devices and energy storage and conversion. The strongest connection can be achieved by mechanical interlocking of both materials, i.e. by increasing the adhesive surface area and by creating hooking structures. Functionalizing the surface by etching mesopores into the Si creates an interlocking structure which can drastically increase the mechanical integrity of the Si-metal composite. A complete pore filling of the structure can be achieved by depositing at low current densities and by using an electrolyte with a high micro throwing power, i.e. with a high ability to fill coat through-holes. However, preventing the metal ions from penetrating the porous structure or even controlling the penetration depth of the metallization is much more challenging by electrochemical means.In this contribution, we present an inexpensive and easily scalable method to control the penetration depth of a Ni layer into mesoporous Si (Ni@Si) that is not making use of macromolecular Ni-complexes. Instead, the process exploits the hydrophobic nature of freshly etched, and hydrogen-terminated Si. In combination with an aqueous Ni-electrolyte, such a hydrophobic mesoporous Si leads to the Cassie-Baxter state where the liquid will not enter the pores, leaving them air-filled. A pre-treatment of the porous silicon was shown to restrict the Ni deposition to a tunable depth. The penetration depth should be chosen about twice as deep as the pore diameter to get a strong mechanical connection.In addition to tailoring the surface energy of the porous Si through the pre-treatment, it is of great importance to choose the right plating parameter. In this contribution we will discuss how voltage and current profiles should be adapted to the electrochemical system and how these parameters get influenced by factors such as temperature, electrolyte flow, passivation kinetics, etc. Our method enables a homogeneous nucleation of Ni grains within the pre-treated pore openings.We demonstrate that the resulting interlocked Ni@Si metallization is well suited for a layer transfer process of a full-scale 15.6 x 15.6 cm2 wafer. The interconnection can even withstand the cycling of Si in a battery. Si, being the anode material with the highest known gravimetric capacity for Li-ion batteries, can expand and shrink by a factor of 4 during lithiation and delithiation, respectively. These enormous volumetric changes lead to a fracturing and cohesive failure of the Si, which is the main challenge in commercializing pure Si anodes (without any binder and conductive carbon). The Ni@Si interlocking structure we have developed provides an interface that can withstand these large volumetric changes without showing signs of delamination of the porous Si from the deposited Ni current collector by adhesive failure.

Development of Eco-Friendly Binders for Silicon Anodes in All-Solid-State Batteries Under Low Operating Pressure

The growing demand for vehicle electrification and sophisticated energy storage systems is driving research into lithium-ion batteries (LIBs) with high energy density. Employing inorganic materials as solid electrolytes (SEs) presents a compelling strategy to enhance the energy density and safety profile of these batteries. Nonetheless, the integration of Li metal anodes (LMAs) in all-solid-state batteries (ASSBs) still presents dendrite issues, and without specific protective layers like C-Ag, cycle stability remains a challenge. In contrast, Si anodes, which are not subject to these limitations, may offer a viable alternative. However, Si anodes in LIBs are prone to extreme volume expansion (> 300%) during charge-discharge cycles, causing fractures and loss of electrical contact. Si ASSBs can have electrodes in the form of pure Si and a composite with the SEs. Recent studies suggest that each exhibits different failure mechanisms. Specifically, in the case of pure Si, numerous vertical cracks in the electrode and delamination with SE layer have been reported. In low-operating pressure, the resistance to electronic conduction in Si anode is further exacerbated. ASSBs present significant environmental concerns related to their manufacturing and recycling processes, which frequently incorporate hazardous substances such as NMP solvent and fluorinated polymers, including PVDF and PTFE. To commercialize ASSBs, two issues must be resolved.In our study, we designed an aqueous-process-based binder for eco-friendly strategies and utilized it for low pressure operating Si ASSBs. Additionally, the binder significantly contributes improving electrical conductivity during the delithiation process with adhesion properties, as observed by an electrical conductivity measurement cell. The NCM/Si full cell exhibited high discharge capacity at 30°C and 5 MPa with high rates. Our design demonstrates enhanced performance of ASSBs under reduced pressure conditions, addressing a critical aspect of practical applicability.[1] H. S. Tan Darren et al., Science 2021, 373, 1494.[2] H. Huo et al., Nat. Mater. 2024, 23, 543.

Si-Based Composite Anodes with Long Cycle Life for Lithium-Ion Batteries Achieved By Synergistic Effects of Elastic and Stiff Silicides

A composite electrode comprising LaSi2 and pure Si exhibits good charge–discharge cycling performance, even with a degrading capacity after repeated cycles. Before cycling, a metallographic structure was formed in which the Si phase was finely dispersed in the LaSi2 matrix phase; hence, the elastic LaSi2 relieves the stress generated by Si and suppresses electrode disintegration.1 In contrast, prior to capacity degradation, the metallographic structure transformed into a form in which the LaSi2 phase was surrounded by the Si matrix phase; the positional relationship between the two phases was reversed, and LaSi2 could not relieve the stress from Si. In the case of a composite electrode with CrSi2, which possesses stiff mechanical properties to withstand the stress generated by Si, the metallographic structural changes after cycling were suppressed, resulting in good cycling stability. Herein, we considered that the addition of stiff silicides as a third phase to the LaSi2/Si composite could further improve the cycle life by suppressing microstructure inversion. Composite comprising elastic LaSi2, stiff MSi2 (where M = Cr, Mo, Nb, Ta, Ti, or W), and elemental Si were prepared by mechanical alloying method, and the composite electrodes fabricated using gas-deposition (GD) method. The prepared GD electrode was mounted in a coin-type cell as the working electrode. We used a Li metal sheet and glass fiber filter as the counter electrode and separator, respectively. Additionally, we used 1mol dm–3 lithium bis(fluorosulfonyl)amide dissolved in N-methyl-N-propylpyrrolidinium bis(fluorosulfonyl)amide as an ionic liquid electrolyte. Galvanostatic charge-discharge tests were conducted in constant current mode with a charge capacity limitation of 1000 mA h g(Si)–1. In this study, the capacity of the silicides was ignored: the silicide-alone and Si-alone electrodes stored Li, whereas the silicide in the silicide/Si electrodes did not exhibit the reversible capacity.2 Figure 1 shows the cycle life of the LaSi2/MSi2/Si electrodes with the Vickers hardness of MSi2. The cycle life was shortest when WSi2, with the stiffest mechanical properties (hardest Vickers hardness), was used. The cycle life improved as the stiffness of MSi2 lowered. When NbSi2 was added, superior cycling performance was achieved, maintaining a reversible capacity of 1000 mA h g(Si)–1 for approximately 1800 cycles. This exceptional performance was achieved based on the synergistic effects of stiff and elastic silicides. In contrast, the cycle life was adversely decreased when TiSi2, which possessed the lowest stiffness, was used. This trend was observed when LaSi2 was used as the elastic silicide, and the same trend may not be obtained when combined with other elastic silicides. This study provides new insights into the effects of silicide functions on the charge–discharge characteristics of composite electrodes.1) Y. Domi, H. Usui, K. Nishikawa, and H. Sakaguchi, ACS Appl. Nano Mater., 4, 8473 (2021).2) Y. Domi, H. Usui, K. Nishikawa, H. Sakaguchi, et al., Electrochemistry, 88, 548 (2020). Figure 1

The Development of Nano Si Materials in the Application of Lithium-Ion Batteries Anode

Electric vehicles (EVs) have become a practical alternative to conventional fuel vehicles due to their environmental friendliness, high energy efficiency, low operating costs, etc. In EVs, lithium-ion batteries (LIBs) play a crucial role. It provides a power source for EVs and directly affects their performance. Among them, LIBs with silicon nanomaterials as negative electrodes show great potential in improving EV performance. This article aims to conclude Si-based anode LIBs’ present challenges and introduce advanced optimization methods with nano-Si material according to these challenges. It starts with the principle of Li-ion storage in Si. Then, problems faced by pure Si anodes and the preliminarily improved Si-based anodes are listed. Finally, further optimization methods in the nano Si anodes during these years are introduced. The optimization methods mainly include improving the service life of nano-Si-based anode and reducing the cost of manufacture. This comprehensive review provides reference and inspiration for developing Si-based anode LIBs applied in EVs.

Effect of drugs of various groups on the pharmacokinetics of cefotaxime in comparison with their effect on lymphatic tissue drainage

Introduction. The lymphatic system plays a key role in spreading pathogens, including those causing intraabdominal infections. An urgent task of pharmacology is to create methods for the targeted delivery of antibiotics to lymphatic vessels and intestinal tissues. One approach is to use agents acting as endolymphatic conductors to achieve a high drug concentration in the lymphatic system. Aim. To evaluate the effect of various drugs on the concentration of cefotaxime, a third-generation antibiotic, in blood and intestinal tissues, as well as on lymphatic drainage in experiments on mice. Materials and methods. We investigated the effect of hyaluronidase (HLRD), bovgialuronidase azoximer (BovGLRD+Az), terrilitin (TRL), papaya milky juice (PMJ ), sodium heparin (HepS ), aprotinin (APRT), azoximer bromide (AzBrom), furosemide (FRSD) and sodium deoxyribonucleate (DRN) on the removal time of lymphotropic dye from mouse mesentery and the cefotaxime concentration in blood plasma and intestinal tissues by high-performance liquid chromatography. Results. HLRD reduced the time of dye removal from the mesentery by 26.2%, BovGLRD+Az – by 33.5%, TRL – by 36%, PMS – by 23.1%, HepS – by 30.1%, APRT – by 34.6%. The differences in lymphostimulating activity between these drugs were not statistically significant. AzBrom and FRSD increased the dye removal time by 8.3% and 6%, respectively; the DRN had no effect. HLRD, BovGLRD, TRL, PMJ, HepS and APRT increased the CF concentration in blood and intestinal tissues 1.5 and 24 hours after injection, in contrast to the single injection of antibiotic. AzBrom increased the CF concentration only after 1.5 hours. FRSD increased the antibiotic concentration in intestinal tissues but not in blood plasma. The DRN did not affect the studied indicators. Conclusion. Lymphostimulating drugs HLRD, BovGLRD, TRL, PMJ, HepS and APRT effectively direct the antibiotic to the lymphatic system and can be used for lymphotropic therapy.

Polyacrylonitrile and aluminum metal dual functionalization interconnected network for superior lithium storage in silicon anode

Currently, silicon-based anode is one of the most promising anode materials that can be applied in next-generation lithium-ion batteries. However, the high activity of the electrode–electrolyte interface and low electronic conductivity of Si anode during the cycling process greatly limits its large-scale application. Aluminum (Al) is the metallic current collector known to promote electronic conductivity and lithium-ion transfer at low cost. However, to our knowledge, scalable interface engineering incorporating Al with carbonized polymer has not been reported. Herein, a polyacrylonitrile (PAN) and aluminum metal dual functionalization interconnected network is achieved via a simple sol-gel method followed by high-temperature calcination to obtain a stable solid electrolyte interphase (SEI) while allowing fast Li+ transmission. The calculated diffusion energy barrier for lithium ions in Al is 0.2198 eV, significantly lower than that in Cu and Fe. Benefiting from the enhanced interfacial protection and kinetics of Si with polyacrylonitrile/Al, the prepared Si@Al@CPAN anode exhibits high lithium storage capacity (2034.90 mAh/g after 150 cycles at 0.84 A/g). At the same time, the prepared Si@Al@CPAN anode outperforms the pure Si anode in rate performance at 12.6 A/g (1116.75 mAh/g vs. 2.84 mAh/g). The present work delivers new design ideas for high-performance Si anode with a multi-functionalization interface.

Polycrystalline inclusion-free growth of thick, lattice-matched SiGeC with high substitutional Carbon concentrations up to 2%

Lattice-matched SiGeC with ~20% of Ge was grown at 550°C, 10 Torr on a 300 mm Si substrate in an industrial standard Reduced Pressure Chemical Vapor Deposition reactor using commercially available Si2H6/GeH4/SiH3CH3 precursors. Thicknesses exceeding 250 nm resulted in cluster formation in SiGeC with [C]Sub~2.0% and [C]Int~0.4%, with a surface density up to 6.13x106 µm-2. Room temperature photoluminescence measurements showed that the clusters were non-radiative defects and Transmission Electron Microscopy, using the ASTAR system, proved they were polycrystalline with random orientation. Cluster-free growth was achieved for 1 µm thick SiGeC with [C]Sub~1.0% and no interstitial carbon atoms, however, without lattice-matched growth on a Si substrate. Injecting HCl during a co-flow process resulted in a smooth surface with a RMS roughness of 0.23 nm and a reduction of [C]Intfrom ~0.7% down to ~0.1%, close to the detection limit of X-ray Photoelectron Spectroscopy at 0.1%. This led to a significant cluster surface density reduction down to 1.15x104 µm-2. The injection of HCl caused an increase in the Ge concentration from 19.7% up to 28.9% and a non-lattice-matched growth. A Cyclic Deposition Etch (CDE) process resulted in no [C]Int reduction, but significantly reduced the cluster surface density down to 4.60x104 µm-2. CDE-grown SiGeC was lattice-matched to the Si substrate and yielded a smooth surface with a RMS roughness of 0.22 nm. This enabled the growth of high crystalline quality, thick, lattice-matched layers on a 300 mm Si substrate with material properties beyond pure Si.

Evaluation of Band Structure of Single Crystalline Si-Rich SiSn thin Film

We evaluated the bandgap energy and optical properties of single-crystalline silicon-tin (Si1-x Sn x ) thin films utilizing Photoluminescence (PL), spectroscopic ellipsometry (SE), and X-ray photoelectron spectroscopy (XPS). The PL and SE results showed that the indirect and direct bandgap energy decrease with increasing Sn fraction. Furthermore, the change in the direct bandgap energy is larger than the indirect bandgap energy. This shows that Si1-x Sn x approaches the direct transition type. Then, the Sn fraction from the indirect-to-direct bandgap is estimated to be 47.2%. In addition, XPS results showed that the difference in valence band maximum between Si1-x Sn x and pure Si increased depending on Sn fraction. This is responsible for the decrease in the indirect and direct bandgap energy.

Bimetallic FeCo-MOFs mediated Au nanorods etching for the multi-colorimetric and photothermal immunosensing of illegal additive

With the rapid expansion of the health food industry, the scope of safety supervision has also increased. However, traditional instrument detection methods cannot meet the requirements for the rapid on-site detection. Hence, the development of a rapid, precise, and simple method for the analysis of illegal additives in health foods is of great importance. In this work, by using FeCo-MOFs as mimetic peroxidase to mediate Au nanorods (Au NRs) etching, a dual-mode immunosensor based on multi-colorimetric and photothermal signals was fabricated to detect furosemide (FUR). In multi-colorimetric channel, the localized surface plasmon resonance (LSPR) peaks of Au NRs shifted blue, resulting in multi-color changes from red to gray to blue and finally to purple. In photothermal channel, the photothermal effect of Au NRs decreased, resulting in temperature changes. In the range of 1.0 × 10−5-1.0 × 10−2 μg/mL, both LSPR peak blue shift and temperature changes were linearly correlated with the logarithm of FUR concentration, with the detection limits were 4.9 × 10−6 and 8.5 × 10−6 μg/mL, respectively. Furthermore, its concentration can be accurately and intuitively assessed through the observation of vivid colorimetric changes. This advancement offers a highly promising approach for the on-site detection of FUR, facilitating timely and efficient monitoring, thereby significantly enhancing regulatory compliance and ensuring consumer safety.

Enabling Si‐Dominant Anodes: Influence of Neutralization Degree of Polyacrylic Acid on Low‐Cost Micron‐Sized Silicon Anode in High‐Energy Li‐Ion Full Cell

AbstractMicron‐sized silicon is a promising low‐cost, abundant material to increase the energy density of lithium‐ion batteries. Nevertheless, significant volume change and therefore excessive solid electrolyte interphase (SEI) growth lead to fast capacity fading. In this work, polyacrylic acid (PAA) with different neutralization degrees is used for the fabrication of Si anodes for practical applications. The electrochemical performance in full pouch cells reveals that the increase in neutralization degree of PAA up to 70 % enhances the overall performance by improved electrode properties, higher first cycle efficiency (FCE up to 78.1 % at C/3) and better capacity retention (85.4 % after 150 cycles at 1 C) over cycling, while with even higher neutralization degrees (such as 80 %) the performance declines. Since proper mixing of the slurry is another important factor, we optimized the mixing procedure by increasing the solid content of the slurry, which has shown positive influence on the electrochemical performance and electrode properties. To summarize, this work shows full cell 1 C cycling until capacity retention of 85 % after 150 cycles with pure Si microparticle anodes for 70 % neutralized PAA as well as increased C‐rate performance up to 5 C. Post‐mortem, less degradation on electrode and particle level is observed.

A facile and effective strategy for modifying combustion of Zr/KClO4 via adding Si

As a commonly applied ignition composition, Zr/KClO4 has attracted various interests and plenty of efforts have been made to improve the combustion performance. In this study, Si nanoparticles were incorporated into Zr/KClO4 by sonication. Around 2.5× peak pressure and 9.2× reactivity were achieved by Si/50%Zr/KClO4 when compared to Zr/KClO4. In addition, the peak pressure and pressurization rate of Si/Zr/KClO4 ternary systems are all superior to ones of both Zr/KClO4 and Si/KClO4 binary systems. The synergetic effect of Si/Zr/KClO4 is a combination of shorter ignition delay of Zr/KClO4 and more gas production of Si/KClO4, which is also reflected on the higher flame propagation rate of Si/Zr-based thermites than composites with pure Si or Zr as the fuel. Meanwhile, the heat release during the redox reaction has been measured. The results show ∼700–1000 J/g higher energy release than Zr/KClO4, and higher combustion efficiency can be attained by ternary systems than binary ones. Thus, adding Si powders is an effective way to improve the energetic behavior of Zr/KClO4 ignition composition, and Si/Zr/KClO4 ternary composites can be a promising candidate for application in pyrotechnics.