Hydrogen In Silicon Research Articles

Co-optimizing of H-curing, stress, and thermal annealing—A more effective way for realizing FEOL-BEOL compatible eMRAM chip

Metallization, plasma, and thermal annealing used in magneto-resistive random access memory integration differs significantly from traditional interconnection processes, usually resulting in the device performance deterioration of metal-oxide-silicon field-effect transistors. Commonly used methods, such as hydrogen postalloying, may not be effective to recover performance when magneto-resistive random access memory is integrated. The study focused on the interplay between hydrogen content in the dielectric films, wafer configuration induced by film stress, and thermal annealing during the chip fabrication process. Post-thermal annealing can enhance the release of hydrogen from the dielectric films, which can repair the silicon–hydrogen bond breakage resulting from magneto-resistive random access memory integration. However, this process can also worsen wafer bowing in an undesired direction which is detrimental to the performance of metal-oxide-silicon field-effect transistors. Consequently, utilizing silicon nitride with specific hydrogen content, in conjunction with post-thermal annealing, can improve effectively both p-type and n-type metal-oxide-silicon field-effect transistors. This approach holds significant potential for application in more advanced technological nodes since it is compatible with traditional process and does not require more advanced fabrication equipment. Additionally, the resulting embedded magneto-resistive random access memory chips maintain competitive magnetic tunneling junction reliability in term of endurance and reflow resistivity.

Design of physical and functional properties of zeolitic porous monoliths by combining different foaming additives

Self-supporting zeolitic foams were synthesized by a geopolymer gel conversion process, employing silicon powder and hydrogen peroxide as foaming additives. The influence of silicon and hydrogen peroxide combination on the physical properties, mechanical characteristics, and pore distribution was studied. Correlations between these properties were drawn. This approach allows to manufacture porous monoliths tuned in terms of zeolite type and amount and characterized by bulk density ranging between 573 and 762 kg/m3 and thermal conductivity 0.33–0.53 W/mK. Pore structure, size, and distribution were dominated by the type of foaming agent: the foamed samples showed the presence of two classes of pores, the first of the order of magnitude of 1 μm, the second of the order of magnitude of 100 μm. The use of hydrogen peroxide enhanced the porosity in the meso-macropore range (0.1–5 μm). The hydrothermal treatment performed on the foamed geopolymer allowed to achieve the crystallization of zeolites within the solid geopolymer. Mainly FAU and LTA were the zeolitic phases present in the foams, whereas the use of silicon as foaming agent locally increased the Si/Al ratio on the geopolymer surface, promoting the nucleation of FAU.

Influence of foaming additives on the porous structure and properties of lightweight geopolymers based on ash–slag waste

Lightweight geopolymer is a promising thermal insulation material that conserves energy used for heating and cooling buildings. This study investigates foaming agents that influence the porous structure and properties of geopolymer foams based on ash–slag waste from thermal power plant using a 12 M sodium hydroxide solution, waterglass, and foaming agents (30 % hydrogen peroxide solution, aluminum, silicon, and zinc powders). The study demonstrates the feasibility of foaming geopolymers by water evaporation without foaming additives, where the best density of 949 kg/m3 and compressive strength of 4.2 MPa were achieved in samples foamed by microwave radiation, but such properties cannot attribute geopolymers as lightweight. Foaming with H2O2 is hard to synchronize with geopolymerization reactions. Aluminum and silicon powders lead to rapid reactions in alkaline conditions, resulting in uneven pore sizes. Zinc powder was the most effective foaming agent, producing materials with a density of 331 kg/m3 and compressive strength of 1.17 MPa, and it also integrates into the geopolymer gel structure. The foaming process should occur at room temperature. Elevated temperatures increase curing rates and result in incomplete geopolymerization, preventing uniform pore formation. Synthesized geopolymers are suitable for building insulation, basements, underground pipelines, and utility networks.

Fabrication of superhydrophobic all-biomass aerogels with ultralight, elasticity and degradability for efficient oily wastewater treatment

Oily wastewater has seriously threatened the water ecology and human health. Superhydrophobic biomass-based aerogels are ideal candidates to remedy the oily wastewater, but facing challenges for the usage of toxic small molecules crosslinker and the rational construction of elasticity. Herein, we employed the natural non-toxic citral as crosslinker, and then constructed a superhydrophobic chitosan/bamboo cellular fibers aerogel (S-CS/BCF-A) with ultra-light, high elasticity and degradation performances. Wherein the hydrolysis of methyltrichlorosilane produced silicon hydride and hydrogen chloride, enhanced the hydrophobicity of the aerogel surface and partially reduced rigidity of the pore walls, respectively. The S-CS/BCF-A displayed outstanding fatigue durability, which benefited for its lamellar-fiber interweaved structure. In addition, this aerogel could undergo tape-peeling, UV radiation, and organic solvents immersion without superhydrophobic variation, even in seriously abrasing that the surface still maintained high hydrophobicity. The as-made aerogel possessed high oil adsorption capacity (17.95–44.57 g/g), combined with pump-supported device for effectively recovering large-area oil spills (66,348 L·m−2·h−1). Furthermore, the resultant aerogel could efficiently separate the immiscible oil-water mixture and emulsifying wastewater (types of Oil-in-Water and Water-in-Oil emulsions). This work provides a rational design method for constructing the elastic, durable and biodegradable aerogels, used for speedy and economical separation of oil-water mixtures.

RBOH-dependent H2O2 burst induced by silicon dioxide nanoparticles establishes systemic acquired acclimation in quinoa under lead toxicity

The role of silicon dioxide nanoparticles (nSiO2) and hydrogen peroxide (H2O2) in heavy metal tolerance of plants has been well defined; however, their interaction together remains largely unknown. Therefore, two experiments were conducted to determine whether RBOH-dependent signaling is involved in nSiO2-induced systemic lead (Pb) acclimation in Chenopodium quinoa. In the first experiment, quinoa leaves were sprayed with nSiO2 (0, 2, 4 mM) under various Pb concentrations (0, 200 and 400 µM). After 12 h, an H2O2 burst, and higher transcription levels of RBOHD and PCS1 genes (encoding NADPH oxidase and phytochelatin synthase) were recorded in leaves of nSiO2-treated plants. After 15 days, Pb toxicity reduced growth parameters, and Chl a, Chl b contents and increased electrolyte leakage, and foliar spray with nSiO2 reversed this tendency. In the second experiment, foliar application of 4 mM nSiO2 minimized intracellular H2O2 and O2˙¯ and reduced malondialdehyde content and leaf Pb concentration under 400 µM Pb. While, this treatment increased the content of reduced ascorbate, and thiol compounds and enhanced the activities of superoxide dismutase and ascorbate peroxidase not only in leaves but also in untreated roots. However, H2O2 scavenging with DMTU and the inhibition of RBOH-dependent signaling by DPI aggravated Pb phytotoxicity and impaired the beneficial effects of nSiO2 on aforementioned attributes; thereby reduced tolerance index in both leaves and roots. Together, our pharmacological and molecular evidence for the first time unraveled that RBOH-dependent H2O2 burst plays vital role in triggering nSiO2-induced systemic acquired acclimation in Pb-stressed plants.

N2 cleavage by silylene and formation of H2Si(μ-N)2SiH2

Fixation and functionalisation of N2 by main-group elements has remained scarce. Herein, we report a fixation and cleavage of the N ≡ N triple bond achieved in a dinitrogen (N2) matrix by the reaction of hydrogen and laser-ablated silicon atoms. The four-membered heterocycle H2Si(μ-N)2SiH2, the H2SiNN(H2) and HNSiNH complexes are characterized by infrared spectroscopy in conjunction with quantum-chemical calculations. The synergistic interaction of the two SiH2 moieties with N2 results in the formation of final product H2Si(μ-N)2SiH2, and theoretical calculations reveal the donation of electron density of Si to π* antibonding orbitals and the removal of electron density from the π bonding orbitals of N2, leading to cleave the non-polar and strong NN triple bond.

Enhancement of strength and water resistance of macro-defect free （MDF） gypsum modified by pregelatinized starch and hydrogen silicone oil

Gypsum, as a building material with renewable and environmentally friendly characteristics, is severely limited due to its poor mechanical properties and water resistance. Here, this paper investigates pregelatinized starch and hydrogen silicon oil modified macro-defect free (MDF) gypsum composite prepared by pressing. The compressive strength, water absorption, and softening coefficients of foamed MDF gypsum composite were subjected to strict testing. The hydration products, microtopography and pore structure was characterized using XRD, FTIR, SEM and LF-NMR. The result shows that the compressive strength of MDF gypsum composite with 5 % pregelatinized starch was 82.4 MPa, a 44.5% increase compared to the dry blank group, whilst water absorption also rose by 7.8%. Additionally, the compressive strength of MDF gypsum composite with 5 % pregelatinized starch and 1% hydrogen silicon oil was 123.9 MPa, 225.2% higher than that of the dry blank group. The water absorption rate decreases to less than 1.2%. Pregelatinized starch and hydrogen silicone oil assist in the accumulation and arrangement of crystals, while also reducing the space between them. The enhancement mechanism of compressive strength and water resistance of MDF gypsum involves pore filling by pregelatinized starch, as well as crystal contact point modification including stronger adhesion by the pregelatinized starch and hydrophobic properties of hydrogen silicon oil.

Orally Administered Silicon Hydrogen Nanomaterials as Target Therapy to Treat Intestinal Diseases.

The occurrence and development of inflammatory bowel diseases (IBDs) are inextricably linked to the excessive production of reactive oxygen species (ROS). Thus, there is an urgent need to develop innovative tactics to combat IBDs and scavenge excess ROS from affected areas. Herein, silicon hydrogen nanoparticles (SiH NPs) with ROS-scavenging ability were prepared by etching Si nanowires (NWs) with hydrogen fluoride (HF) to alleviate the symptoms associated with IBD by orally targeting the inflamed colonic sites. The strong reductive Si-H bonds showed excellent stability in the gastric and intestinal fluids, which exhibited efficient ROS-scavenging effects to protect cells from high oxidative stress-induced death. After oral delivery, the negatively charged SiH NPs were specifically adsorbed to the positively charged inflammatory epithelial tissues of the colon for an extended period via electrostatic interactions to prolong the colonic residence time. SiH NPs exhibited significant preventive and therapeutic effects in dextran sodium sulfate-induced prophylactic and therapeutic mouse models by inhibiting colonic shortening, reducing the secretion of pro-inflammatory cytokines, regulating macrophage polarization, and protecting the colonic barrier. As determined using 16S rDNA high-throughput sequencing, the oral administration of SiH NPs treatment led to changes in the abundance of the intestinal microbiome, which improved the bacterial diversity and restored the relative abundance of beneficial bacteria after the inflamed colon. Overall, our findings highlight the broad application of SiH-based anti-inflammatory drugs in the treatment of IBD and other inflammatory diseases.

Correlation study between LeTID defect density, hydrogen and firing profile in Ga-doped crystalline silicon

Correlation study between LeTID defect density, hydrogen and firing profile in Ga-doped crystalline silicon

Theory of reactions between hydrogen and group-III acceptors in silicon

Theory of reactions between hydrogen and group-III acceptors in silicon

Evolution of Cu-In Catalyst Nanoparticles under Hydrogen Plasma Treatment and Silicon Nanowire Growth Conditions.

We report silicon nanowire (SiNW) growth with a novel Cu-In bimetallic catalyst using a plasma-enhanced chemical vapor deposition (PECVD) method. We study the structure of the catalyst nanoparticles (NPs) throughout a two-step process that includes a hydrogen plasma pre-treatment at 200 °C and the SiNW growth itself in a hydrogen-silane plasma at 420 °C. We show that the H2-plasma induces a coalescence of the Cu-rich cores of as-deposited thermally evaporated NPs that does not occur when the same annealing is applied without plasma. The SiNW growth process at 420 °C induces a phase transformation of the catalyst cores to Cu7In3; while a hydrogen plasma treatment at 420 °C without silane can lead to the formation of the Cu11In9 phase. In situ transmission electron microscopy experiments show that the SiNWs synthesis with Cu-In bimetallic catalyst NPs follows an essentially vapor-solid-solid process. By adjusting the catalyst composition, we manage to obtain small-diameter SiNWs-below 10 nm-among which we observe the metastable hexagonal diamond phase of Si, which is predicted to have a direct bandgap.

Atmospheres as windows into sub-Neptune interiors: coupled chemistry and structure of hydrogen–silane–water envelopes

ABSTRACT Sub-Neptune exoplanets are commonly hypothesized to consist of a silicate-rich magma ocean topped by a hydrogen-rich atmosphere. Previous work studying the outgassing of silicate material has demonstrated that such atmosphere–interior interactions can affect the atmosphere’s overall structure and extent. However, these models only considered SiO in an atmosphere of hydrogen gas, without considering chemical reactions between them. Here, we couple calculations of the chemical equilibrium between H, Si, and O species with an atmospheric structure model. We find that substantial amounts of silane, SiH4, and water, H2O, are produced by the interaction between the silicate-rich interior and hydrogen-rich atmosphere. These species extend high into the atmosphere, though their abundance is greatest at the hottest, deepest regions. For example, for a 4 M⊕ planet with an equilibrium temperature of 1000 K, a base temperature of 5000 K, and a 0.1 M⊕ hydrogen envelope, silicon species and water can comprise 30 per cent of the atmosphere by number at the bottom of the atmosphere. Due to this abundance enhancement, we find that convection is inhibited at temperatures ≳2500 K. This temperature is lower, implying that the resultant non-convective region is thicker, than was found in previous models that did not account for atmospheric chemistry. Our findings show that significant endogenous water is produced by magma–hydrogen interactions alone, without the need to accrete ice-rich material. We discuss the observability of the signatures of atmosphere–interior interaction and directions for future work, including condensate lofting and more complex chemical networks.

Study of porous silicon layer effect in optoelectronics properties of crystalline silicon

In this research, we experimentally and numerically demonstrate the beneficial effect of superficial porous silicon layer in the optoelectronics properties of multi-crystalline silicon. The hydrogen and oxygen-rich porous silicon layer was formed using vapor etching method. From laser beam induced current (LBIC) simulations, we found that the hydrogen and oxygen-rich porous silicon layer used in mc-Si surface acts as a good surface passivation and a potential candidate for electronic quality and optoelectronics properties improvement. As a result, the generated current of treated silicon is 5 times greater as compared to reference substrate, which led to a 50% increase of the minority carrier diffusion length, 25% decrease in the recombination velocity of the minority carrier and the reflectivity reduced from 38 to 3% of the related sample.

Amelioration of Salt-Induced Damage on Paeonia ostii ‘Fengdan’ by Exogenous Application of Silicon

To investigate the amelioration of salt-induced damage on Paeonia ostii ‘Fengdan’ by exogenous silicon, we analyzed the photosynthetic and physiological characteristics of 1.5-year-old ‘Fengdan’ seedlings under NaCl stress by applying exogenous silicon (0, 0.75, and 1.5 mmol/L). Our results showed that the contents of the photosynthetic pigments chlorophyll a, chlorophyll b, and carotene, the transpiration rate, stomatal conductance, and intercellular CO2 were significantly enhanced under salt stress when silicon treatment was applied, implying that the net photosynthetic rate was greatly improved. In addition, the plant height, stem thickness, and above-ground dry biomass of tree peony seedlings were effectively increased under salt stress with low-concentration silicon (0.75 mmol/L) treatment, along with osmotic substance (SS, SP, and Pro) content, total polyamine (TP) contents, and the activities of antioxidant-related enzymes (SOD, POD, and CAT) and polyamine-related synthetases (ADC, ODC, and SAMDC). In the low-concentration silicon treatment, malondialdehyde (MDA), hydrogen peroxide (H2O2), and superoxide anions (O2−) were transformed quickly, which eventually reduced cell oxidative damage and improved seedling tolerance. This is an important finding in the understanding of how exogenous low-concentration silicon can alleviate salt-induced damage and promote the growth of tree peony seedlings, thus providing a new perspective on tree peony cultivation.

Influence of intrinsic amorphous silicon passivation layer on the dark-state stability of SHJ cells

Silicon heterojunction (SHJ) solar cells with a two-densities stacked intrinsic hydrogenated amorphous silicon (i-a-Si:H) thin film passivated crystalline silicon surface have high VOC and efficiency. We investigated the dark stability of cells varied with the microstructure of i-a-Si:H layers. It has been found that the dark degradation is mainly from the change in the silicon hydrogen bonded configuration associated with voids size. Furthermore, the less degradation exists on cells with thicker dense i-a-Si:H layers, which results from the high bonded hydrogen content after the enhanced light-soaking (LS) and less change in voids during the dark storage in the i-a-Si:H layers. The microstructure changes, including bonded hydrogen content, voids size, and voids quantity, are related to the initial microstructure of i-a-Si:H layers. This can be illustrated by two actions of non-bonded hydrogens immersed in the undense part of the silicon network. As a result, to enhance the bonded hydrogen content in the i-a-Si:H layers is a preferred method to improve the dark stability of SHJ solar cell after LS.

Time evolution of donor activation at low temperatures with co-implantation of phosphorus and hydrogen in silicon

We report on the study of the donor activation behavior at low temperatures using subamorphizing implantation of phosphorus and hydrogen to develop three-dimensional integrated circuits. We show that the activation efficiency of phosphorus 0° implantation angle is superior to that at 7° due to the broad defect and donor profiles. At 370 °C, the carrier concentration was enhanced by hydrogen co-implantation at a dose of 1015 cm−2. However, the enhancement quickly decayed, and the carrier concentration at 400 °C was lower than that in the sample without hydrogen. The change in the activation behavior suggests that the enhancement in the carrier concentration was due to the defect complexes generated by hydrogen implantation. By eliminating defect complexes, the passivation of phosphorus by hydrogen atoms became evident. At 500 °C, hydrogen caused phosphorus deactivation at the beginning of the annealing process. The carrier concentration then recovered, indicating dehydrogenation during further annealing.

Enhancing toughness, flame retardant, hydrophobic and dielectric properties of epoxy resin by incorporating multifunctional additive containing phosphorus/silicon

Developing epoxy resins with superior toughness, flame retardant and hydrophobic as well as dielectric properties remains a huge challenge. Herein, an epoxy additive (ETP) was prepared by grafting phosphorus-containing molecules into the skeleton of silicone resin through silicon hydrogen addition reaction. Through such a design, the obtained ETP imparted Bisphenol A epoxy resin (DGEBA) with excellent flexibility, fire safety, hydrophobicity and dielectrical property. When only 6 wt% of ETP was introduced into the DGEBA system, the resulting product (ETP-6) passed the V-0 level in the UL-94 test with a high limiting oxygen index of 29.8 %, which could be ascribed to the presence of phosphorus and silicon element. Meanwhile, compared with neat DGEBA, the peak heat releases and smoke emissions of ETP-6 were reduced by 32.7 % and 37.8 % during the combustion. Additionally, ETP also imparted the cured product with excellent hydrophobic and dielectric properties, as well as superior toughness (114.5 % increase in impact strength) due to its “rigid and flexible” silicone skeleton and good dispersion. This work opens up a new strategy for developing high-performance and multifunctional epoxy resin additives with potential versatile applications.

Silicon–Hydrogen Bonding Configuration Modified by Layer Stacking Sequence in Silicon Heterojunction Solar Cells

Recent improvements in highly efficient crystalline silicon (c-Si) solar cells have relied on surface passivation. Hydrogen plays a crucial role in the surface passivation of silicon heterojunction (SHJ) solar cells because Si–H bonds passivate dangling bonds in amorphous silicon and on the c-Si surface. In this work, we demonstrate that the Si–H bonding configuration is modified by layer stacking sequence for SHJs. The quality of surface passivation strongly correlates with low-temperature hydrogen effusion from the SHJ structure. Our results show that the deposition of doped layers on intrinsic amorphous silicon supplies additional hydrogen to the amorphous/crystalline heterostructure. Moreover, the deposition of a p-layer modifies the microstructure of the intrinsic layer underneath, whereas depositing an n-layer does not induce structural changes. We suggest that the low-temperature hydrogen effusion characteristics can be used as a sensitive indicator for examining the passivation quality of SHJ solar cells.

Optimization and sensitivity analysis of a multi-product solar grade silicon refinery: Considering environmental and economic metrics

Today, one of the main lines of solar energy development is the creation of environmentally friendly, waste-free and inexpensive solar grade silicon production technologies. Presently, the main solar grade silicon production technologies are based on the reduction of silicon hydrogen chloride compounds (trichlorosilane, tetrachlorosilane and silane). This paper will examine the results of the optimization of a multi-product silicon refinery, where the objective functions are Profit and Eco-indicator99. Seven scenarios are considered for the work. The best scenario (S4) showed a tendency to maintain a balance between Profit (98.66 M$/y) and the environmental indicator Eco99 (6.04 MP/y). Similarly, a sensitivity analysis was carried out by varying the market prices of each of the products obtained (solar grade silicon, TEOS at different purities, and chlorosilanes) with an increase of 10% and a decrease of 10%, resulting in multiple production scenarios depending on what the market dictates. By increasing the cost of solar grade silicon by 10%, the multi-product refinery achieves the highest profit (151.84 [M$/y] with an environmental impact of 9.8 [MP/y]), and by decreasing the cost of the same silicon by 10%, the lowest environmental impact is achieved (36 [M$/y] with an environmental impact of 3 [MP/y]).

Preparation of degradable bio-based silicone/epoxy hybrid resins towards low dielectric composites

Epoxy resins are well-known adhesive materials, however, the high dielectric constant (Dk) limited their application in microelectronic devices. Additionally, non-degradability is a bottleneck for all thermosetting resins, and the discarded resins posed the great threat to environment. Herein, a bio-based eugenol epoxy was grafted onto the polymethylhydrosiloxane (PMHS-x) main chain via a hydrosilylation reaction to simultaneously lower the Dk and enable degradability. The curing kinetics of bio-based silicone/epoxy hybrid resins with methyl hexahydrophthalic anhydride (MHHPA) or 4,4′-diaminodiphenylmethane (DDM) were studied. The cured resins exhibited low Dk and hydrophobicity by taking advantage of the low polarity, large molecular volume and high dissociation energy of the siloxane segments. The polysiloxane degradation process took place under alkaline conditions, allowing the retrieval of reinforced fibers from the composites. To better illustrate the superiority of the bio-based silicone/epoxy hybrid resins, quartz fiber reinforced composites were prepared. Compared to the commercial epoxy based composite, the impact strength of the PMHS-x with a silicon hydrogen content of 0.8 × 10-2 mol·g−1 was increased by 26.5 %, meanwhile, the Dk was decreased by 16.7 %. The bio-based silicone/epoxy hybrid resins not only alleviated the environmental pollution but also provided a reliable approach for fiber recycling from epoxy composites. The low polarity and degradability were integrated into bio-based silicone/epoxy hybrid resins, which provided a novel way to prepare environment-friendly materials suitable for microelectronic devices.