Influence Of Nitrogen Implantation Research Articles

Influence of nitrogen ion implantation on the electrophysical properties of the gate dielectric of power MOSFETs

Power MOS-transistors with vertical structure are investigated. Additionally, in some devices, ion implantation of nitrogen with energies of 20 and 40 keV was carried out in a dose range of 1 ⋅1013–5 ⋅ 1014 cm –2 through a sacrificial oxide 20 nm thick. For one group of wafers, rapid thermal annealing was first carried out, then oxide removal (forward order), for the other group – in the opposite sequence (reverse order). It was found that with the additional doping of nitrogen ions in doses of 1⋅1013–5 ⋅ 1013 cm –2 with energy of 20 keV, an increasing of gate dielectric charge to breakdown for both types of annealing is observed. The maximum effect occurred for the samples at a dose of nitrogen ions of 1⋅1013 cm –2 with the forward heat treatment order. This is due to the interaction of nitrogen atoms with dangling bonds of the Si – SiO2 interface during annealing, as a result of which strong chemical bonds are formed that prevent charge accumulation on the surface of the Si – SiO2 interface. It is assumed that the main contribution to the gate leakage current is made by the tunneling of charge carriers through traps.

Influence of nitrogen ion implantation on surface charge accumulation and dissipation of polytetrafluoroethylene

To suppress the accumulation of charge on the surface of polytetrafluoroethylene (PTFE) material, radio frequency nitrogen plasma was generated to perform plasma immersion ion implantation (PIII) on the PTFE surface to improve its surface properties. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), water contact angle measurement, surface resistivity measurement and surface potential attenuation measurement were performed on the samples of PTFE material before and after injection to analyze the changes in surface composition and physical properties of PTFE samples after ion implantation treatment. Based on the theory of isothermal surface potential attenuation, the energy levels and density distributions of the surface traps were calculated. The results show that after nitrogen ion implantation, the main change in the chemical composition of the surface of the PTFE material is the destruction and conversion of its own molecular structure, and part of the CF2 structure is transformed into the CF and CF3 structures, resulting in shallower trap levels on the sample surface. The results also show that the water contact angle rose to about 140°, which is about 27° higher than that of the unprocessed sample. The surface resistivity drops to 3×1015 Ω, which is two orders of magnitude lower than that of the unprocessed samples. After 1 min of corona discharge on the surface, the amount of accumulated charge on the surface of the PTFE material processed with nitrogen ion implantation decreased, and the rate of dissipation increased. This is because the lower surface trap level is conducive to surface charge trapping, and the reduction in surface resistivity also promotes the dissipation process of surface charge along the surface. The curve of trap level distribution on the surface of PTFE sample also confirmed this.

Ion implantation of copper oxide thin films; statistical and experimental results

Ion implantation is one of the interesting way to tune the electrical and optical properties of metal oxides. In this regard, doping copper oxide with nitrogen is of interest on account of its potential to enhance the properties of copper oxide. Herein, we have investigated the influence of nitrogen ion implantation on the properties of copper oxide thin films, prepared using DC magnetron sputtering. The crystal structure, surface morphology, and optical properties of pristine and ion implanted copper oxide were investigated by means of X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and UV–visible spectrophotometer. The results of XRD demonstrated a mixture of CuOCu2O and Cu2O (as dominant phase). Additionally, the ion implanted sample illustrated a lower grain compared to the pristine sample. An increase of 2–3 order was obtained in the internal strain upon implementation of nitrogen into the samples that could be ascribed to the formation of non-uniform grains and an increment in lattice imperfection.The results of surface micrographs demonstrated a remarkable change on the surface of samples and the appearance of interconnected holes after ion implementation. The band gap was tuned and increased from 2.27 to 2.36 eV upon ion implantation that is largely owing to the influence of the quantum size of copper oxide during implantation. Our results show that the nitrogen ion implantation (N-type doping) is a useful way to tune the properties of materials that are applicable for variety of photovoltaic and optoelectronic devices. Moreover, the 3-D surface micro-texture characteristics of pristine and nitrogen ion implanted copper oxide thin films were quantitatively investigated using AFM, fractal, and stereometric analyzes.

Effect of Ti Substrate Ion Implantation on the Physical Properties of Anodic TiO2 Nanotubes

The influence of nitrogen-ion implantation on the titanium (Ti) surface is studied. The nontreated Ti and the Ti treated with ion implantation were anodized in an ethylene-glycol-based electrolyte solution containing 0.3 wt% ammonium fluoride (NH4F) and 3 vol% deionized (DI) water at a potential of 60 V for 1 h at room temperature. The current density during the growth of the TiO2 nanotubes was monitored in-situ. The surface roughnesses of the Ti substrates before and after the ion implantation were investigated with atomic force microscopy (AFM). The surface roughness was lower for the treated Ti substrate. The morphology of the anodic TiO2 nanotubes was studied by using field-emission scanning electron microscopy (FESEM). Clearly, the titanium nanotubes grown on the treated substrate were longer. In addition, some ribs were observed on their walls. The optical band gap of the anodic TiO2 nanotubes was characterized by using a diffuse reflection spectral (DRS) analysis. The anodic TiO2 nanotubes grown on the treated Ti substrate revealed a band gap energy of approximately 3.02 eV.

The influence of nitrogen implantation on the electrical properties of amorphous IGZO

In this study, nitrogen (N) implantation was adopted to regulate the carrier concentration and the Hall mobility of amorphous Indium Gallium Zinc Oxide (a-IGZO) films. The Hall Effect measurement demonstrates that the increase of implantation fluence can decrease the carrier concentration of a-IGZO by three orders to 1016cm−3, which attributes to the reduction of oxygen defects. The addition of nitrogen atoms can result in the increase of Hall mobility to 9.93cm2/Vs with the subsequent decrease to 6.49cm2/Vs, which reflects the reduction of the average potential barrier height (φ0) to be 22.0meV with subsequent increase to 74.8meV in the modified percolation model. The results indicate that nitrogen can serve as an effective p-type dopants and oxygen defect suppressors. N-implantation with an appropriate fluence can effectively improve the Hall mobility and reduce the carrier concentration simultaneously.

The influence of nitrogen ion implantation on the tribological properties of piston rings made of Hardox and Raex steels

The implantation of nitrogen, carbon, and oxygen can be used for enhancing the tribological properties of critical components for internal combustion engines. Hardox and Raex steels have very similar strength parameters as for steel used for piston rings in internal combustion engines. An essential criterion when selecting material for the production of piston rings is a low friction factor and a low wear index. The aim of this study was to determine the extent to which these parameters can be enhanced by nitrogen ion implantation. Samples were implanted with nitrogen ions with 65 keV energy and the fluence of implanted ions set to 1.1017 N + /cm2. Friction and wear measurements were performed on a pin-on disc stand. The results demonstrate that implantation with nitrogen ions significantly reduces the friction factor and wear of Hardox 450 and Raex 400 steels. Implantation can and should be used for enhancing the tribological properties of steel used for friction elements in internal combustion engines, particularly when heat treatment is excluded. Final elements can be subjected to implantation, as the process does not change their dimensions.

The influence of nitrogen implantation on tribological properties of AISI H11 steel

Nitrogen ion implantation can be used to improve the surface mechanical properties (hardness, wear) of steel by modifying the near-surface layers of these materials. In this research, AISI H11 hot work tool steel was implanted with 120 keV nitrogen ions at the fluence of (1 ÷ 10) × 1016 N+/cm2. The concentration profiles of nitrogen ions implanted into H11 steel were measured by RBS and these were compared with the profiles created using SATVAL and SRIM computer simulation codes. The surface morphology was examined and elemental analysis was performed using SEM, AFM, EDS, and RBS. Wear tests were conducted with the use of the pin-on-disc method. The worn surfaces of samples were observed by means of SEM, EDS, WDS and CEMS. The surface layers were characterised using a nano-hardness test. A significant improvement in nano-hardness and wear resistance has been found with increasing implantation fluences. The decreased wear rate and increased friction coefficient caused by the long-range effect extended to a 19-fold greater depth than the range of the implanted nitrogen ions. The investigations have shown that the long-range effect is also induced by nitrogen diffusion during a local increase in temperature in the friction process. Nitrogen implantation modified the nature of surface wear, decreasing adhesive wear and increasing oxidizing wear. The oxidizing wear predominated after the implantation at the fluence of 1 × 1017 N+/cm2.

Corrosion resistance and magnetostrictive properties of (Tb0.3Dy0.7)Fe2 alloy modified by nitrogen ion implantation

The corrosion resistance and magnetostriction of (Tb0.3Dy0.7)Fe2 alloy were investigated for different nitrogen doses of 5×1015, 5×1016, 5×1017, 1×1018 ions/cm2 and average ion energy of 140 kV. The phase and elements concentration in the implanted layer were examined by X-ray diffraction and auger electron spectroscopy, respectively. The aqueous corrosion studies were carried out in 3.5% NaCl solutions. It was found that corrosion resistance had improved substantially with respect to the untreated substrates. The corrosion resistance was maximum at a dose of 5×1017 ions/cm2, and saturation in corrosion improvement was noticed at a higher dose, 10×1017 ions/cm2. In contrast, the results of magnetostriction tests before and after ion implantation showed that the influence of nitrogen ion implantation on the magnetostrictive properties turned out to be small. Finally, a model was applied to interpret the influ ence of nitrogen implantation on the magnetostriction in the light of the information provided by the experimental results in this study.

Influence of nitrogen implantation on thermoluminescence of synthetic quartz

Thermoluminescence (TL) of synthetic quartz exposed to beta irradiation following implantation with 60 keV N+ ions at fluences ranging between 1 × 1014 and 5 × 1015 ions/cm2 is reported. The glow curve measured at 5°C/s typically consists of a prominent peak near 110°C, studied in this work, and minor glow peaks at around 130°C and 190°C. The TL intensity of the main peak increased both with implantation and with fluence of implantation. The dependence of the intensity on the heating rate and fluence suggests that the implantation introduces new defects that may possibly act as recombination centres. The increase in TL intensity with the heating rate exhibited by implanted samples has been observed in other luminescence materials. This anti-quenching phenomenon has been described as a competition effect between multiple luminescence pathways in luminescence materials. Kinetic analysis of the main glow peak using the initial rise, various heating rate and glow-curve deconvolution methods shows that the activation energy of the main peak is about 0.7 eV with no systematic change due to ion fluence.

Influence of nitrogen implantation on thermoluminescence of synthetic quartz

Thermoluminescence (TL) of synthetic quartz exposed to beta irradiation following implantation with 60 keV N+ ions at fluences ranging between 1 × 1014 and 5 × 1015 ions/cm2 is reported. The glow curve measured at 5°C/s typically consists of a prominent peak near 110°C, studied in this work, and minor glow peaks at around 130°C and 190°C. The TL intensity of the main peak increased both with implantation and with fluence of implantation. The dependence of the intensity on heating rate and fluence suggests that the implantation introduces new defects that may possibly act as recombination centres. The increase in TL intensity with the heating rate exhibited by implanted samples has been observed in other luminescence materials. This anti-quenching phenomenon has been described as a competition effect between multiple luminescence pathways in luminescence materials. Kinetic analysis of the main glow peak using the initial rise, various heating rate and glow curve deconvolution methods shows that the activation energy of the main peak is about 0.7 eV with no systematic change due to ion fluence.

Influence of high-dose nitrogen implantation on the positive charge density of the buried oxide of silicon-on-insulator wafers

The influence of nitrogen implantation on the properties of silicon-on-insulator buried oxide using separation by oxygen implantation was studied. Nitrogen ions were implanted into the buried oxide layer with a high-dose of 1016 cm-2. The experimental results showed that the positive charge density of the nitrogen-implanted buried oxide was obviously increased, compared with the control sampes without nitrogen implantation. It was also found that the post-implantation annealing caused an additional increase of the positive charge density in the nitrogen implanted samples. However, annealing time displayed a small effect on the positive charge density of the nitrogen implanted buried oxide, compared with the significant increase induced by nitrogen implantation. Moreover, the capacitance-voltage results showed that the positive charge density of the unannealed sample with nitrogen implanted is approximately equal to that of the sample annealed at 1100 ℃ for 2.5 h in N2 ambient, despite an additional increase brought with annealing, and the buried oxide of the sample after 0.5 h annealing has a maximum value of positive charge density. According to the simulating results, the nitrogen implantation resulted in a heavy damage to the buried oxide, a lot of silicon and oxygen vacancies were introduced in the buried oxide during implantation. However, the Fourier transform infrared spectroscopy of the samples indicates that implantation induced defects can be basically eliminated after an annealing at 1100 ℃ for 0.5 h. The increase of the positive charge density of the nitrogen implanted buried oxide is ascribed to the accumulation of implanted nitrogen near the interface of buried oxide and silicon, which caused the break of weak Si-Si bonds and the production of positive silicon ions in the silicon-rich region of the buried oxide near the interface, and this conclusion is supported by the results of secondary ion mass spectrometry.

Influence of nitrogen implantation into the buried oxide on the radiation hardness of silicon-on-insulator wafers

In order to improve the total-dose radiation hardness of the buried oxide of separation by implanted oxygen silicon-on-insulator wafers, nitrogen ions were implanted into the buried oxide with a dose of 1016 cm−2, and subsequent annealing was performed at 1100 °C. The effect of annealing time on the radiation hardness of the nitrogen implanted wafers has been studied by the high frequency capacitance-voltage technique. The results suggest that the improvement of the radiation hardness of the wafers can be achieved through a shorter time annealing after nitrogen implantation. The nitrogen-implanted sample with the shortest annealing time 0.5 h shows the highest tolerance to total-dose radiation. In particular, for the 1.0 and 1.5 h annealing samples, both total dose responses were unusual. After 300-krad(Si) irradiation, both the shifts of capacitance-voltage curve reached a maximum, respectively, and then decreased with increasing total dose. In addition, the wafers were analysed by the Fourier transform infrared spectroscopy technique, and some useful results have been obtained.

An XPS study on the influence of nitrogen implantation on the passive layers developed on different tempers of AA7075 aluminum alloy

AbstractThe present work analyzes the chemical effect of nitrogen implantation on the passive layer formed on different tempers of AA7075 aluminium alloy, T6 and T73. The experimental results from XPS depth profiles show that the air‐formed passive oxide, on both tempers, is mainly formed by Al2O3, highly hydrated, with Mg2+ and small amounts of Zn2+. The only difference between both tempers is the amount of Zn2+, significantly higher in T73‐temper and located in the outermost region of the passive oxide layer.Nitrogen implantation produces a modified layer containing a nitride phase, identified as AlN probably nanocrystalline, as the BE of N1s at 397.4 ± 0.2 eV indicates and GAXRD has confirmed. Moreover, nitrogen implantation changes the composition of the Al2O3 oxide by increasing the hydration content; no traces of Zn2+ are detected in its composition. Copyright © 2010 John Wiley & Sons, Ltd.

Influence of nitrogen ion implantation energies on surface chemical bonding structure and mechanical properties of nitrogen-implanted silicon carbide ceramics

Nitrogen ions were implanted into silicon carbide ceramics (N +-implanted SiC) at different ions energies. The surface chemical bonding structure of N +-implanted SiC ceramics were investigated by using X-ray photoelectron spectroscopy (XPS). The hardness of N +-implanted SiC ceramics was measured using nano-indenter, and the friction and wear properties of the N +-implanted SiC/SiC tribopairs were studied using ball-on-disk type tribo-meter in water lubrication. The wear tracks were observed using non-contact surface profilometer and scanning electron microscope (SEM). The results showed that the surface roughness of N +-implanted SiC ceramic was higher than that of SiC ceramic, and some chemical bonds such as Si–N, C–C, C N and C–N bonds were formed in N +-implanted layer besides Si–C bonds. In comparison of SiC ceramic’s hardness, the hardness of N +-implanted SiC ceramics at 30 and 50 keV was higher while that at 65 keV was lower. Under water lubrication, the friction coefficient and the specific wear rates for the N +-implanted SiC/SiC tribopairs were all lower than those of the SiC/SiC tribopairs, and displayed the lowest values at 50 keV. According to XPS analysis, it was concluded that the high wear resistance and low friction coefficient for the N +-implanted SiC/SiC tribopairs were attributed to the formation of carbon rich composite on the surface of N +-implanted SiC ceramics.

Effect of nitrogen ion implantation on in vitro corrosion behaviour of NiTi

In the last decade, different surface modifications have been developed to enhance the biocompatibility of NiTi shape memory alloys. The present paper deals with the influence of nitrogen ion implantation on corrosion behavior of NiTi in Hank’s solution. Nitrogen implantation at 150 keV with nominal doses ranged from 0.5x10 17 to 8x10 17 ion cm –2 , were used. Mechanical surface characterization was carried out by nanohardness, corrosion mechanism evaluation by electrochemical polarization and impedance spectroscopy (EIS) tests and surface composition by XPS spectra. The results point out the benefit of the N-implanted for corrosion resistance at a suitable dose 2x10 17 ion cm -2 and an increase of the mechanical properties with the doses.

Influence of nitrogen implantation on the high temperature oxidation of titanium-base alloys

Nitriding is one of the important surface modifications used to enhance corrosion resistance of materials in addition to improving wear resistance due to high hardness of the nitrided surface. However, its effect depends not only on the nature of the materials but also on the treating and environmental conditions. In the present investigation, the influence of nitrogen implantation on the high temperature oxidation of titanium-base alloys, IMI 834, Ti–Al–Nb and Ti–Al–Nb–Mo, has been studied at 800 and 900 °C. Nitriding enhances the oxidation resistance of titanium-base alloys. However, the influence of nitriding is found to depend on the nature and concentration of alloying elements present in the titanium-base alloys. It is also found that the nitriding effect is fluence and temperature dependent. The oxidation resistance of all the titanium-base alloys was enhanced considerably for the initial 20 h. After prolonged exposure, the effect of nitriding was nullified in the case of IMI 834, had no effect on TiAlNb and a significant effect on TiAlNbMo. XRD was used to identify the phases, and SEM and EDS to study the morphology of oxides scales and their compositions formed during high temperature exposure. Metallography and EPMA were used to study the cross sections and elemental distribution after oxidation.

Influence of nitrogen ion implantation on tribological properties of tool steel NC10

This paper deals with the influence of nitrogen ion implantation on the values of the friction coefficient and wear of tool steel. The friction coefficient and wear of samples were found to decrease with the dose increase of nitrogen ions implanted at 60keV. Improvement of tribological properties was obtained with the energy increase to 120keV with nitrogen ions introduced into the sample. Polyenergetic implantation was used for one sample so as to obtain an even concentration of nitrogen atoms in the whole modified layer and this gave the best tribological results.

Effects of compositional and structural change on the corrosion behaviour of nitrogen implanted Zircaloy-4

Abstract The influence of nitrogen implantation on the corrosion behaviour of Zircaloy-4 was examined by potentiodynamic polarization tests in a chloride and an acid solution, and the results were discussed with structural and compositional variations of implanted layer that was determined by X-ray diffraction (XRD) and Auger electron spectroscopy (AES). The resistance to localized corrosion of Zircaloy-4 was very sensitive to the ion dose and the substrate temperature during the implantation. At substrate temperatures above 200°C, the pitting potential of the nitrogen implanted alloy in deaerated 4 M NaCl at 80°C increased gradually with the ion dose from 350 mVSCE for the unimplanted sample to 990 mVSCE for the alloy implanted with an ion dose of 6×1017 ions cm−2, and then the alloy was immune to pitting when implanted with ion doses greater than about 1×1018 ions cm−2. In contrast to this, the alloy implanted at 100°C exhibited an inferior corrosion resistance to the unimplanted sample irrespective of the ion dose. A drastic increase in the resistance to pitting corrosion in chlorides as well as a significant reduction in the passive current density in acid solution of the implanted alloy, were found to be associated with the formation of ZrN layer with a stoichiometric ratio of N to Zr. The low resistance to localized and general corrosion of the alloy implanted at 100°C was attributed to the increase in structural defects produced by ion bombardment, and to low atomic mobility in the implanted layer.

Influence of nitrogen implantation on the properties of Ti and substoichiometric TiNx films deposited on high speed steel

Ti and TiNx (x < 1) thin films have been deposited on high speed steel (HSS) substrates by reactive sputtering and then N+ implanted. The increase of the N/Ti ratio of the films during deposition is related to a decrease in their roughness, and N+ implantation produces another additional slight decrease of the roughness. The hardness of samples increases with the nitrogen content in the as-deposited samples; nevertheless, N+-implanted Ti coatings show lower values of hardness than reactive sputtered TiNx films. α–Ti, ε–Ti2N, and δ–TiN phases were identified by grazing x-ray diffraction.

Hardness, tribological behaviour and corrosion performance at the very near surface of nitrogen ion-implanted X5CrNi18.10 steel

The influence of nitrogen ion implantation on the hardness, tribological behaviour and corrosion performance at the very near surface of polished X5CrNi18.10 steel was studied. The specimens were implanted with 120 keV N + ions to four different fluences ranging from 10 16 to 10 18 ions cm −2. It was found that hardness, tribological behaviour in terms of wear and friction, and corrosion resistance of the specimens strongly depend on the implantation conditions. The greatest improvement in the surface properties of the steel was achieved at doses between 1 × 10 17 and 5 × 10 17 ions cm −2. Although hardness, wear resistance and friction behaviour were improved noticeably by the implantation, N ion implantation tended to reduce the corrosion resistance of the specimens in KNO 3.