Implantation Energy Research Articles

An Electret-based Implantable Energy Harvester with Liquid Cells (MEMS vs. 3D Printing Fabrication)

An Electret-based Implantable Energy Harvester with Liquid Cells (MEMS vs. 3D Printing Fabrication)

Stretchable Fiber Biofuel Cell by Rewrapping Multiwalled Carbon Nanotube Sheets.

The fiber-type biofuel cell is attractive as an implantable energy source because the fiber can modify various structures and the wound can be stitched like a suture. In addition, in daily life, the biofuel cell is forced by human motion, and stretchability is a critical requirement for real applications. Therefore, we introduce a new type of highly stretchable, stable, soft fiber biofuel cell with microdiameter dimensions as an energy harvester. The completed biofuel cell operated well in fluids similar to human fluids, such as 20 mM phosphate-buffered 0.14 M NaCl solution (39.5 mW/cm2) and human serum (36.6 μW/cm2). The fiber-type biofuel cell can be reversibly stretched up to 100% in tensile direction while producing sustainable electrical power. In addition, the unique rewrapping structure, which traps the enzyme between multiwalled carbon nanotube sheets, enormously enhanced the stability of the biofuel cell when the biofuel cell was repeatedly stretched (the power density retention increased from 63 to 99%) and operated in human serum (the power density retention increased from 29 to 86%). The fiber can be easily woven into various structures, such as McKibben braid yarn, and scaled up by series and parallel connections.

Structural evolution of thermal annealed Si(0 0 1) surface layers fabricated by plasma immersion He+ implantation

Abstract Structural evolution in Si(0 0 1) surface layers after high-dose (D = 5 × 1017 cm–2) low-energy (2 and 5 keV) plasma immersion He+ ion implantation (He+ PIII) and subsequent annealing at 853 and 1073 K was studied by complementary structural sensitive methods (TEM, XRR, RBS, and AFM). Formation of a three-layer structure (amorphous a-SiOx sublayer at the surface, amorphous a-Si sublayer with large size helium-filled bubbles, and heavily damaged crystalline c-Si sublayer containing small-size bubbles and Si nanocrystallites) was observed for both implantation energies. This three-layer structure is retained after annealing. It was shown that the thickness of the oxide sublayer does not depend on implantation energy and does not change after annealing. This amorphous oxide sublayer together with dense top part of the a-Si sublayer forms a cap layer with a thickness of 15 nm that can be considered as a protective layer for the sublayers containing He-filled bubbles and Si nanocrystallites. The Si nanocrystallites were revealed at the boundary of the a-Si and the c-Si sublayers both in as-implanted at 5 keV and annealed samples.

Acceleration of the corrosion reaction of magnesium by Fenton reagents

Magnesium alloys have attracted increased attention for a variety of applications, chief among which are alternative energy and medical implants. The use of biodegradable implants in the complex system of the human body, in which myriad reactions occur, must consider the potential effects of the body’s natural chemical reactions on implant corrosion rates. The aim of this study was to elucidate the synergistic effects of pure Mg and Mg alloys on the Mg corrosion reaction with reagents that participate in the Fenton reaction. We corroborated our results with six different measurement methods (hydrogen evolution rate [HER], gas chromatography [GC], potentiodynamic polarization, inductively coupled plasma [ICP] spectrometry, Auger electron spectroscopy [AES], and scanning electron microscope [SEM]). The results point out that the corrosion and hydrogen evaluation rates of Mg were elevated by the addition of Fenton reagents, divalent iron and hydrogen peroxide, to a saline solution. In the context of Mg-based alloy medical implant development and use, this observation is significant.

Research on ion implantation in MEMS device fabrication by theory, simulation and experiments

Ion implantation is widely utilized in microelectromechanical systems (MEMS), applied for embedded lead, resistors, conductivity modifications and so forth. In order to achieve an expected device, the principle of ion implantation must be carefully examined. The elementary theory of ion implantation including implantation mechanism, projectile range and implantation-caused damage in the target were studied, which can be regarded as the guidance of ion implantation in MEMS device design and fabrication. Critical factors including implantations dose, energy and annealing conditions are examined by simulations and experiments. The implantation dose mainly determines the dopant concentration in the target substrate. The implantation energy is the key factor of the depth of the dopant elements. The annealing time mainly affects the repair degree of lattice damage and thus the activated elements’ ratio. These factors all together contribute to ions’ behavior in the substrates and characters of the devices. The results can be referred to in the MEMS design, especially piezoresistive devices.

Effect of shot-peening treatment on the bio-tribological properties of a Ni+ implantation layer formed on the surface of Ti6Al4V

To improve the bio-tribological properties of the Ti6Al4V surface, the Ti6Al4V alloy was subjected to a shot-peening treatment and a subsequent Ni+ implantation process. The phase composition, phase content and grain size of the resulting Ni+ implantation layer formed on the surface were evaluated via x-ray diffraction. The nano-hardness of the modified layer was measured with a nano-micro mechanical probe. Moreover, after bio-tribological testing, the scratch morphology of the layer was observed with a scanning electron microscope. The results revealed that this layer was composed mainly of Ti2Ni. The shot-peening pretreatment yielded a significant increase in the Ti2Ni content and the nano-hardness of the layer, resulting in grain size refinement of the formation phase. When a Ni+ implantation energy of 45 keV was employed, the Ti2Ni phase content and the grain size of the shot-peened layer increased by 33.6% and decreased by 65.9%, respectively. The corresponding friction coefficients under artificial saliva and a sodium hyaluronate pure water solution decreased by 20.9% and 29.3%, respectively. In the case of samples implanted at an energy of 40 keV, the nano-hardness of the shot-peened layer was 50.8% higher than that of the non-peened layer. Therefore, a shot-peening pretreatment can yield a significant improvement in the properties of the single Ni+ implantation layer on the Ti6Al4V surface.

Analysis the Effect of Control Factors Optimization on the Threshold Voltage of 18 nm PMOS Using L27 Taguchi Method

This research paper is about the investigation of Halo Implantation, Halo Implantation Energy, Halo Tilt, Compensation Implantation and Source/Drain Implantation. They are types of control factors that used in achievement of the threshold voltage value. To support the successfully of the threshold voltage (VTH) producing, Taguchi method by using L27 orthogonal array was used to optimize the control factors variation. This analysis has involved with 2 main factors which are break down into five control factors and two noise factors. The five control factors were varied with three levels of each and the two noise factors were varied with two levels of each in 27 experiments. In Taguchi method, the statistics data of 18 nm PMOS transistor are from the signal noise ratio (SNR) with nominal-the best (NTB) and the analysis of variance (ANOVA) are executed to minimize the variance of threshold voltage. This experiment implanted by using Virtual Wafer Fabrication SILVACO software which is to design and fabricate the transistor device. Experimental results revealed that the optimization method is achieved to perform the threshold voltage value with least variance and the percent, which is only 2.16%. The threshold voltage value from the experiment shows -0.308517 volts while the target value that is -0.302 volts from value of International Technology Roadmap of semiconductor, ITRS 2012. The threshold voltage value for 18 nm PMOS transistor is well within the range of -0.302 ± 12.7% volts that is recommendation by the International Roadmap for Semiconductor prediction 2012.

Control of the residual stress gradients in copper films by inert ion implantation

In this work, we studied the effect of inert ion implantation using helium and xenon ions on residual stress gradients in copper films. A copper microcantilever beam array was fabricated on a (1 0 0) silicon wafer by conventional bulk micromachining. The as-fabricated copper microcantilevers showed upward bending deformation as a result of positive residual stress gradient in films. Helium and xenon ions were implanted at various doses and energies into microcantilevers before releasing them from substrates. The magnitudes and signs of residual stress gradients were effectively controlled by both helium and xenon ion implantation and depended on implantation energy and ionic dosages. The mechanism of residual stress control appeared to involve counterbalancing residual stress gradients with compressive residual stresses induced by volume expansions of implanted regions and the direct effect of surface modification by ion bombardment.

Effect of ultraprecision polishing techniques on coherence times of shallow nitrogen-vacancy centers in diamond

We investigate the correlation between surface roughness and corresponding T2 times of near-surface nitrogen-vacancy centers (~10 nm/5 keV implantation energy) in diamond. For this purpose we compare five different polishing techniques, including both purely mechanical as well as chemical mechanical approaches, two different substrate sources (IIa Technologies and Element Six) and two different surface terminations (O- and H-termination) during nitrogen-vacancy forming. All coherence times are measured and compared before and after an oxygen surface treatment at 520 °C.We find that the coherence times of shallow nitrogen-vacancy centers are surprisingly independent of surface roughness.

Revisited study of fluorine implantation impact on negative bias temperature instability for input/output device of automotive micro controller unit

We investigate the effect of fluorine implanted in the polycrystalline silicon (poly-Si) gate and source/drain (S/D) region on negative bias temperature instability (NBTI) improvement. It is found that there is a trade-off implantation energy dependence of NBTI between fluorine in the poly-Si gate and that in the S/D region. Fluorine implanted in the poly-Si gate contributes to NBTI improvement under low energy implantation. On the other hand, NBTI is improved by fluorine implanted in the S/D region under high energy. We propose that the two-step implantation process with high and low energy is the optimum condition for NBTI improvement.

Optical properties of silicon-vacancy color centers in diamond created by ion implantation and post-annealing

Silicon-vacancy (SiV) color centers have been created in diamond by ion implantation and post annealing at LABEC (Florence). A wide range of implantation depths (0–2.4 μm) and fluences (108–1015 cm−2), along with a variety of substrates (single and poly-crystals) have been explored. The photoluminescence properties of the SiV centers have been studied at room temperature, including their single-photon emission characteristics. Single-photon emitters have been obtained at the lower-end of the implantation fluences range. They exhibit a short excited-state lifetime (~1 ns), a strong zero-phonon transition with a narrow linewidth (~1.6 nm) and a very small inhomogeneous broadening (0.015 nm), features that qualify them for application in quantum optical technologies. The activation yield of SiV centers has been assessed under different experimental conditions. It has been found to be independent of the implantation energy and in the range of 3% after thermal annealing.

Defect-Related Electroluminescence in the 1.2–1.7 μm Range from Boron-Implanted Silicon at Room Temperature

The room-temperature electroluminescence (EL) band in the 1.2–1.7 μm range in boron-implanted silicon with implantation energy of 50 keV and 700 keV was investigated. This band is attributed to the defects in the implantation region introduced by implanted ions. The defects are unstable under the annealing temperature as low as 350°C. The EL intensity of the device implanted at 700 keV is much stronger than that of the device implanted at 50 keV due to the higher defect concentration and the improved minority carrier injection ratio. The absence of this band in photoluminescence measurements indicates that the luminescence band can only be electrically driven. Further enhancement of this EL band can be achieved by optimizing the implantation parameters.

Ultra-low-energy ion-beam synthesis of nanometer-separated Si nanoparticles and Ag nanocrystals 2D layers

2D networks of Si and Ag nanocrystals have been fabricated in the same SiO2 matrix by Ultra-Low-Energy Ion-Beam-Synthesis. Our synthesis scheme differs from a simple sequential ion implantation and its key point is the control of the matrix integrity through an appropriate intermediate thermal annealing. Si nanocrystal layer is synthesised first due to high thermal budget required for nucleation, while the second Ag nanocrystal plane is formed during a subsequent implantation due to the high diffusivity of Ag in silica. The aim of this work is to show how it is possible to overcome the limitation related to ion mixing and implantation damage to obtain double layers of Si-NCs and Ag-NCs with controlled characteristics. For this, we take advantage of annealing under slight oxidizing ambient to control the oxidation of Si-NCs and the Si excess in the matrix. The nanocrystal characteristics and in particular their position and size can be adjusted thanks to a compromise between the implantation energy, the implanted dose for both Si and Ag ions and the intermediate annealing conditions (atmosphere, temperature and duration).

Implantable Energy Harvesting Stents for Transcutaneous Wireless Monitoring of Peripheral Artery Disease

More than five million adults in U.S. are affected by the peripheral artery disease. Current wireless stent monitors are unsuitable to use in the thigh. In this paper, wireless powering and communication with implanted stents were investigated. Specifically, we investigated the effects of thigh tissue morphology and tissue thickness variations on wireless power gain and electromagnetic safety when using skin-contact touch probe antennas. Thigh simulation models were derived from anthropometric data for the diseased population. Power gain and specific absorption rate were determined for each variation. To corroborate human model simulation results, a power-to-frequency converter was designed, benchmarked, and implanted within ex vivo porcine tissue. The experiments showed the most realistic simulations reported so far that have the best agreement with measured results. This paper indicates that touch probe powered stent systems can safely deliver significant power to an implant. This research enables frequent at-home monitoring to replace costly in-hospital quarterly check-ups.

Spin properties of dense near-surface ensembles of nitrogen-vacancy centers in diamond

We present a study of the spin properties of dense layers of near-surface nitrogen-vacancy (NV) centres in diamond created by nitrogen ion implantation. The optically detected magnetic resonance contrast and linewidth, spin coherence time, and spin relaxation time, are measured as a function of implantation energy, dose, annealing temperature and surface treatment. To track the presence of damage and surface-related spin defects, we perform in situ electron spin resonance spectroscopy through both double electron-electron resonance and cross-relaxation spectroscopy on the NV centres. We find that, for the energy ($4-30$~keV) and dose ($5\times10^{11}-10^{13}$~ions/cm$^2$) ranges considered, the NV spin properties are mainly governed by the dose via residual implantation-induced paramagnetic defects, but that the resulting magnetic sensitivity is essentially independent of both dose and energy. We then show that the magnetic sensitivity is significantly improved by high-temperature annealing at $\geq1100^\circ$C. Moreover, the spin properties are not significantly affected by oxygen annealing, apart from the spin relaxation time, which is dramatically decreased. Finally, the average NV depth is determined by nuclear magnetic resonance measurements, giving $\approx10$-17~nm at 4-6 keV implantation energy. This study sheds light on the optimal conditions to create dense layers of near-surface NV centres for high-sensitivity sensing and imaging applications.

Effects of Fluorine on the NBTI Reliability and Low-Frequency Noise Characteristics of p-MOSFETs

The concurrent effect of fluorine implantation with various energy and dose on reliability and low-frequency noise characteristics of p-MOSFETs was investigated. The $\Delta $ VT degradation that represents device lifetime of p-MOSFETs with fluorine implantation under negative-bias temperature instability stress was less than that without fluorine implantation. The device lifetimes were improved as the fluorine implantation energy and dose increase. The power law exponent $n $ with the fluorine implantation was larger than that without fluorine implantation. This was related to boron diffusion within the gate oxide because the F atoms enhance the diffusivity of the boron. The difference of flicker noise levels between simulation and measurement data at 1 kHz was much greater than that at 10 Hz, which means that F atoms were mainly located near the Si/SiO2 interface rather than in the bulk oxide. The fluorine implantation reduced the ID-RTS noise amplitude, which was believed to contribute to the effective passivation of the dominant traps within the gate oxide. Also, the flicker noise was less dependent on implantation energy. But, flicker noise was reduced with increasing implantation dose. Therefore, fluorine implantation is potentially significant for reducing low-frequency noise as well as improving reliability characteristics.

Analysis of Anti-JFET for 600V VDMOS and HCI Reliability

In VDMOS device the anti-JFET concentration has important role for determining the breakdown voltage and on-resistance of the device. Because higher N-drift doping concentration can provide the very best on-resistance of the device but also decrease breakdown voltage. It also has a proportional relationship with threshold voltage degradation. In this paper, we report the anti-JFET implantation energy influence effect electric potential distribution, the highest impact ionization shifted from the silicon surface to deeper. It will have less hot carrier impact, and we have found higher breakdown voltage. The anti-JEFT implantation is critical for on-resistance off-state breakdown voltage optimization, However the high field and high impact ionization near the gate region will cause severe hot carrier Injection problem. The general expectation of high voltage VDMOS transistor is to have higher breakdown voltage, less degradation due to hot carrier injection and better on-resistance.

4H-SiC高温激活退火对F离子扩散的影响

离子注入工艺作为SiC MOSFET/Diode器件制造过程的重要工艺过程，离子注入后激活退火的温度直接影响注入后晶格损伤的修复效果以及离子激活的程度，离子注入和激活退火一直是研究的热点和难点。本文主要研究了离子注入后激活退火温度对离子扩散至SiC/SiO2界面处的浓度的影响，离子注入在4H-SiC(0001)面进行，注入元素F，离子注入能量25 KeV，浓度5E13 cm−2，在离子注入后，分别在500℃、700℃、900℃、1100℃下进行激活退火2 min，而后通过二次离子质谱法(SIMS)分析不同温度激活退火后F元素扩散至SiC/SiO2界面处的浓度，以及F元素扩散到背面(C-face(0001))的浓度，实验结果表明随着激活退火温度的增加，SiC材料表面的元素浓度也随之增加，实验结果发现在700℃激活退火时，SiC/SiO2界面处F元素浓度升高明显，并且扩散至C面的元素浓度相对于离子注入激活退火前的样品基本无变化。 The ion implantation is one of the most important processes in SiC MOSFET/Diode devices manufacturing. The ion activation temperature after implantation results has direct impact on the performance of lattice damage repairing and the degree of ion activation. The ion implantation process and activation annealing are hot and difficult research spots. In this paper, the effect of activation annealing temperature on the concentration of SiC/SiO2 interface after ion implantation was studied. The ion implantation was carried out on the 4H-SiC (0001) surface, element F was implanted, the ion implantation energy was 25 KeV and concentration was 5E13 cm−2. And then the samples were annealed at 500˚C, 700˚C, 900˚C and 1100˚C for 2 min, respectively. The concentration of F in Si-face and the diffusion of F element to the back surface (C-face (000-1)) with different activation annealing temperature were also monitored by secondary ion mass spectroscopy (SIMS). It finds that the surface ion concentration increased as the activation annealing temperature increased. The experimental results showed that when activation annealing is at 700˚C, the F ion concentration was increased at SiC/SiO2 interface, and the F ion concentration diffused to the 4H-SiC C-face is substantially unchanged from the sample without ion-implantation activation annealing.

Tailoring the structural and magnetic properties of masked CoPt thin films using ion implantation

The effects of ion implantations through a mask on the structural and magnetic properties of Co80Pt20 films were investigated. The mask was patterned using the self-assembly of diblock copolymers. For implantation, high (40 keV for 14N+ and 100 keV for 40Ar+) and low (7.5 keV for 14N+ and 4.5 keV for 40Ar+) energy 14N+ and 40Ar+ ions were used to modify the structural and magnetic properties of these films. X-ray diffraction and TRIM simulations were performed for understanding the structural changes due to ion implantations. These results revealed the intermixing of Co atoms in lower layers and lattice expansion in Co80Pt20 magnetic and Ru layers. A lateral straggling of Co caused an increase in the exchange coupling in the masked region. Depletion of Co atoms in Co80Pt20 layer caused a decrease in the anisotropy constant, which were further confirmed by the alternating gradient force magnetometer and magnetic force microscopy results. The magnetic force microscopy images showed an increase in domain width and domain wall width confirming the above-mentioned effects.

Characterization of photoresist films exposed to high-dose implantation conditions

Alternative approaches are now required to fulfill the strict requirements of photoresist (PR) dry strip process after high-dose implantation. A better understanding of the PR degradations induced by the ion bombardment during the implantation is thus required. In this study, in-depth characterizations of PR films after arsenic and phosphorus-high-dose implantation have been made. The influence of the dopant species (As or P) as well as the implantation energy has been investigated. The experimental results have then been confronted to simulations performed with stopping and range of ions in matter (SRIM). The experimental results show the formation of a “crust layer” enriched in carbon and depleted in oxygen and hydrogen whose density, hardness, and elastic modulus are higher than the nonimplanted PR (pristine). SRIM simulations confirm that the PR degradation is mainly due to crosslinking phenomenon. Chemical analyses have revealed that the dopants are present in their elemental and oxidized forms in the PR and that they are also linked to the PR carbon atoms. The knowledge of the dopants' chemical environment is key information to understand the presence of residues after dry strip processes and develop alternative processes to avoid their formation.