Effect Of Post-implantation Annealing Research Articles

Effects of Si ion implantation on the surface and electrical characteristics of epitaxial GaSb

GaSb was grown epitaxially on semi-insulating GaAs (001) substrates using molecular beam epitaxy. The effect of varying ion energy and fluence of Si ion implantation on the structure, topology, chemical composition and electrical characteristics of GaSb epilayers is investigated. Si ion implantation was done with energies of 50, 100, and 150 keV and the fluence ranging between 1 × 1012 - 1 × 1015 ions/cm2. The effects of post-implantation annealing have also been investigated. High-resolution x-ray diffraction ω-2ϴ scans clearly revealed the damage and the recovery post-annealing.The surface morphology observed by atomic force microscopy was found to change significantly only at the highest fluence of 1 × 1015 ions/cm2. Raman spectroscopy was used to determine the implantation-induced disorder as well as the evolution of surface oxides; the latter being also corroborated with x-ray photoelectron spectroscopy. Hall measurement has been used to confirm the doping characteristics in the implanted annealed samples. The morphological variations and the mobility are understood from the displacement per atom induced by the ion beam.

Effect of post-implantation annealing on Al–N isoelectronic trap formation in silicon: Al–N pair formation and defect recovery mechanisms

The effect of post-implantation annealing (PIA) on Al–N isoelectronic trap (IET) formation in silicon has been experimentally investigated to discuss the Al–N IET formation and implantation-induced defect recovery mechanisms. We performed a photoluminescence study, which indicated that self-interstitial clusters and accompanying vacancies are generated in the ion implantation process. It is supposed that Al and N atoms move to the vacancy sites and form stable Al–N pairs in the PIA process. Furthermore, the PIA process recovers self-interstitial clusters while transforming their atomic configuration. The critical temperature for the formation/dissociation of Al–N pairs was found to be 450 °C, with which we describe the process integration for devices utilizing Al–N IET technology.

Effect of post-implantation annealing on the current-voltage characteristics of IR photodiodes based on p-HgCdTe

Current-voltage characteristics of IR photodiodes and distributions of charge carriers in n+-n−-p-structures based on vacancy p-doped Hg1 − xCdxTe films with x = 0.22 are examined. Three-dimensional numerical modeling of the distribution of charge carriers and current-voltage characteristics during photodiode annealing is performed. The calculations predict that large tunnel currents in diodes after implantation can result from an elevated (more than 1015 cm−3) concentration of donors in the n−-layer, which enhances tunneling by decreasing the thickness of the space charged region of the n-p-junction, and also from a small (less than 3 µm) depth of the p-n-junction.

이온주입 공정을 이용한 4H-SiC p-n Diode에 관한 시뮬레이션 연구

Silicon carbide (SiC) has attracted significant attention for high frequency, high temperature and high power devices due to its superior properties such as the large band gap, high breakdown electric field, high saturation velocity and high thermal conductivity. We performed Al ion implantation processes on n-type 4H-SiC substrate using a SILVACO ATHENA numerical simulator. The ion implantation model used Monte-Carlo method. We simulated the effect of channeling by Al implantation in both 0 off-axis and 8 off-axis n-type 4H-SiC substrate. We have investigated the effect of varying the implantation energies and the corresponding doses on the distribution of Al in 4H-SiC. The controlled implantation energies were 40, 60, 80, 100 and 120 keV and the implantation doses varied from to . The Al ion distribution was deeper with increasing implantation energy, whereas the doping level increased with increasing dose. The effect of post-implantation annealing on the electrical properties of Al-implanted p-n junction diode were also investigated.

Abnormal Out-Diffusion of Epitaxially Doped Boron in 4H–SiC Caused by Implantation and Annealing

The effects of postimplantation annealing on the homogeneous depth profiles of epitaxially doped B and Al in 4H–SiC were investigated after the ion implantation of various species. We found a marked decrease in the atomic B concentration close to the surface in epitaxially B-doped layers after the implantation of Al, N, or P ions followed by annealing at 1700 °C. On the other hand, the Al profiles in epitaxially Al-doped layers were preserved after the same processes.

Synthesis of cobalt nanoparticles by ion implantation and effects of postimplantation annealing

A study of the synthesis of Co nanoparticles by ion implantation and the effects of postimplantation annealing was carried out. Silica was implanted with 35keV Co+ ion beams to doses ranging from 8×1015to1×1017atoms∕cm2. Nanoparticle size, distribution, and structure were ascertained via transmission electron microscopy measurements, which reveal the presence of spherical nanoparticles in both as-implanted and annealed samples. X-ray photoelectron spectroscopy show the chemical state of the nanoparticles in both as-implanted and annealed samples to be metallic. Temperature-dependent field-cooled and zero-field-cooled, susceptibility measurements indicated superparamagnetic behavior, which is analyzed by accounting for the size dispersion of the nanoparticles. Results showed that the magnetic properties of the specimen can be tailored by implantation conditions. Annealing in vacuum at 900°C for up to 10h leads to an increase of the average nanoparticle size and a broader size distribution. Mie scattering and magnetic force microscopy measurements provide evidence of a strong interaction among the nanoparticles in the annealed samples. The feasibility of obtaining small-dispersion size-controlled synthesis of Co nanoparticles at room temperature is illustrated.

Effect of post-implantation anneal on the electrical characteristics of Ni 4H-SiC Schottky barrier diodes terminated using self-aligned argon ion implantation

The effects of post-implantation annealing on the electrical characteristics of Ni 4H-SiC Schottky barrier diodes terminated using self-aligned Ar + ion implantation have been investigated. Results show that the Ar + edge termination may be modelled as a shunt linear resistive path at low to moderate reverse bias levels and at low forward bias levels. Low temperature (400–700°C) annealing is shown to increase the equivalent resistance of the edge termination by two orders of magnitude without significant effect on the breakdown voltage. Annealing temperatures above 600°C are, however, shown to degrade the on-state performance. A breakdown voltage of 1530 V was achieved on the implanted and annealed samples, representing 90% of the theoretical parallel plane breakdown voltage. Temperature dependent measurements, made over the temperature range 25–400°C show that the equivalent resistance of the edge termination is thermally activated with an exponential temperature coefficient of −0.02 K −1. Behaviour at moderate forward bias levels is typical of thermionic emission whilst operation at high forward bias is dominated by a linear series resistance which shows a quadratic temperature dependence, increasing by a factor of 6 over the range 25–400°C.

Formation of Cu nanoparticles in GaAs using MeV ion implantation followed by thermal annealing

Analytical electron microscopy, high-resolution X-ray diffraction and combined Rutherford backscattering spectrometry and channeling experiments have been used to investigate the radiation damage and the effect of post-implantation annealing on the microstructure of GaAs(100) single crystals implanted with 1.00 MeV Cu+ ions to a dose of ≈ 3×1016 cm-2 at room temperature. The experiments reveal the formation of a thick and continuous amorphous layer in the as-implanted state. Annealing up to 600 °C for 60 min does not result in the complete recovery of the lattice order. The residual disorder in GaAs has been found to be mostly microtwins and stacking fault bundles. The redistribution of implanted atoms during annealing results in the formation of nano-sized Cu particles in the GaAs matrix. The X-ray diffraction result shows a cube-on-cube orientation of the Cu particles with the GaAs lattice. The depth distribution and size of the Cu particles have been determined from the experimental data. A tentative explanation for these results is presented.

Nitridation of diamond and graphite surfaces by low energy N+2 ion irradiation

Low energy 500 eV N+2 ion irradiation of diamond and graphite surfaces has been investigated by AES and XPS in order to model the possibility of carbon nitride formation by ion implantation methods. In this work we present experimental data demonstrating the crucial influence of sample temperature during irradiation on the carbon-nitrogen chemical bonds formation. The distribution of bonding states of the implanted nitrogen is shown to be different for diamond and graphite substrates. The effect of post-implantation annealing and implantation temperature on the distribution of nitrogen bonding states is investigated. Structural effects were assessed by changes in the C(KVV) Auger lineshape fine structure.

窒素イオン注入によるＺｒＮ層の形成と熱処理効果

To study the formation process and thermal stability of ZrN layers under nitrogen ion implantation, zirconium films have been implanted with 15N2 ions of 100keV at doses of from 1×1017 to 10×1017N/cm2, at room temperature and 500°C. Effects of post-implantation annealing were also investigated. The depth distribution of the implanted nitrogen was measured in detail by nuclear reaction analysis using the 15N (p, α γ)12C reaction at Ep=429keV. The structure of the implanted layers was measured by thin film XRD, and hardness was measured by a Knoop microhardness indenter. It was found that nitrogen concentration exceeded 50% in the layers that were just shallower and deeper than the mean projected range of nitrogen for a dose of 7×1017N/cm2. The overstoichiometric layers were eliminated by the subsequent ion implantation and a trapezoidal distribution was obtained at a dose of 10×1017N/cm2. The distribution of nitrogen implanted at 500°C can be explained by thermal diffusion, precipitation of nitrogen in the surface layer, and sputtering by ion bombardment. The structure of the ZrN layer produced by nitrogen implantation at room temperature was improved by 500°C annealing, but thermal diffusion of the implanted nitrogen became obvious at 700°C annealing.

The effect of annealing on the Knoop microhardness of nitrogen implanted Ti6Al4V alloy

The implantation of the Ti6Al4V alloy with nitrogen has been previously studied, and the treatment has been shown to improve the microhardness significantly [R.G. Vardiman, Defect and Diffusion Forum 57/58 (1988) 135, and references therein]. The effects of post-implantation annealing on the properties has not been studied systematically, and this is the principal aim of the RMIT work. Initial results of this study are presented and discussed. It was found that N + implantation of this alloy at 80 keV with fluences varying in the range (0.5–1.5) × 10 17ions/cm 2 caused an improvement in Knoop hardness up to 100%. Rutherford backscattering results show a buried layer containing up to 25% nitrogen in the as-implanted specimens at a depth of 130 nm. After annealing the sample implanted with 1.5 × 10 17 at 705°C, both the nitrogen concentration and the depth of the layer decrease to approximately half of their as-implanted values. The observed reduction in hardness can be attributed to the decrease in the nitrogen concentration of the buried layer, as well as to repair of the lattice. These results may indicate that only a limited amount of TiN forms directly during implantation.

Photoluminescence and magnetic resonance studies of Er3+ in MeV ion-implanted GaAs

The effects of post-implantation annealing have been studied in MeV Er-implanted GaAs by monitoring the Er3+ electron paramagnetic resonance (EPR) signal as well as the Er3+ and near-band-edge photoluminescence (PL) spectra as a function of the anneal temperature. Er3+ PL is observed from several distinct Er sites in the annealed material. In addition, the observed dependences upon anneal temperature suggest that the Er3+ PL is emitted from centers that are not in the Er3+ state at equilibrium. Absolute EPR measurements of the Er3+ concentration indicate that only a small fraction (<0.1%) of the Er in the sample is Er3+.