Showing papers in "Radiation Effects and Defects in Solids in 1970"
IBM1
TL;DR: In this paper, a phenomenological model was proposed to account for the variation of the critical dose required to produce a continuous amorphous layer by ion bombardment with ion, target, temperature, and, with minor additional assumptions, dose rate.
Abstract: The effective annealing of ion implantations in Si is aided by the formation of continuous amorphous layer. The amorphous layer regrows epitaxially at 500–600°C and incorporates the dopant in an electrically active, uncompensated form. A phenomenological model is proposed which, with adjustable parameters, accounts for the variation of the critical dose required to produce a continuous amorphous layer by ion bombardment with ion, target, temperature, and, with minor additional assumptions, dose rate.
405 citations
TL;DR: In this paper, an interpolation rule for ranges and stragglings in amorphous substances is presented. But the agreement of the results with accurate range-calculations is better than ∼10 per cent.
Abstract: Approximations and interpolation rules for ranges and stragglings in amorphous substances are presented. Two energy regions, termed low and intermediate energies, corresponding to the dimensionless energy epsilon being in the intervals 0.002<∊<0.1 and 0.5<∊<10, respectively, are defined. For low energies the projected range is approximately proportional to E2/3 , and for intermediate energies approximately proportional to E. For low energies, approximate stragglings are also obtained. The agreement of the results with accurate range-calculations is better than ∼10 per cent.
176 citations
TL;DR: In this paper, a technique has been developed for automatically counting etched tracks that pass through a thin film, where a spark, passing through the film along a damage track, evaporates a hole in the Al. A second spark is prevented from starting through the same hole, so that the discharge passes successively along each track.
Abstract: The low background of damage track detectors allows them to measure low integrated fluxes of charged particles or neutrons. When good statistical accuracy is desired, the long times required for visual track counting under the microscope may seriously limit the number of measurements, particularly when the track density is low. A technique has been developed for automatically counting etched tracks that pass through a thin film. Very simple and inexpensive equipment is required. The insulating film is placed between a plane, high-voltage electrode and a thin layer of Al. A spark, passing through the film along a damage track, evaporates a hole in the Al. A second spark is prevented from starting through the same hole, so that the discharge passes successively along each track and then stops. Sparks are counted with a scaler. The pattern of holes in the Al provides a visible replica of the pattern of tracks. Track densities from background level to 3000 tracks/cm2 can be measured. Areas up to 100 ...
154 citations
TL;DR: In this paper, the temperature rise in thin metallic foils under intense electron irradiation has been computed as a function of beam conditions, electron energy, and the physical properties of the foil.
Abstract: The temperature rise in thin metallic foils under intense electron irradiation has been computed as a function of beam conditions, electron energy, and the physical properties of the foil. The model due to Gale and Hale was used in conjunction with the corrected Bethe electron energy loss formula for relativistic electrons. Although the nature of the assumptions made renders the results generally unapplicable to low thermal conductivity materials, a set of beam conditions etc. are specific for the particular case of a small temperature rise in a ceramic foil (UO2).
143 citations
TL;DR: In this article, the spatial distribution of the production of a quantity, Q, averaged over many ions incident randomly on a solid for any energy dependent interaction between the ions and target atoms.
Abstract: A method is given for calculating the spatial distribution of the production of a quantity, Q, averaged over many ions incident randomly on a solid for any energy dependent interaction between the ions and target atoms. The method is basically a two step method. First, the spatial distribution of the ions in the solid is followed as the ions lose energy. Then, at each intermediate energy the spatial distribution of Q-production is obtained and the result is integrated over the range of intermediate energies assumed by the ions. Saturation effects are ignored in the procedure so that explicit consideration must be given to saturation effects when applying the method to high dose cases. Annealing and diffusion effects are also ignored, and the method is restricted in applicability to experimental conditions where annealing and diffusion are unimportant. Results of calculations by this method are presented of the depth distribution of energy ultimately deposited into atomic processes for Li7, B11, C...
127 citations
TL;DR: In this paper, the authors used a successive layer removal technique by anodic oxidation and stripping to obtain a depth scale for 1.8 MeVHe+ analyses of lightly disordered samples.
Abstract: Channeling effects on the yield of large angle backscattered energetic H+ or He+ were used to investigate properties of the disorder in Si samples previously implanted with B11 ions at substrate temperatures of -150°C to -50°C. Exposure of the implanted samples to the analyzing beam at room temperature caused a large reduction in the amount of disorder measured. A successive layer removal technique by anodic oxidation and stripping was used to obtain a depth scale for 1.8 MeVHe+ analyses of lightly disordered samples. The results of additional experiments indicate that for 1 MeV He+ in Si the aligned stopping power is about 80 per cent of the random stopping power. Measured and calculated values of the minimum yield X R for the substrate underlying amorphous layers suggested a plural scattering treatment of dechanneling of the analyzing beam using previously measured values of the critical angle. The scattering center distributions calculated from this treatment of dechanneling are presented for ...
81 citations
TL;DR: In this paper, the authors showed that the electrical resistivity and the Hall coefficient of n-type GaAa can be recovered from annealing near 5 and 77 °K with electrons having incident energies between 0.46 and 1.30 MeV.
Abstract: Undoped n-type GaAa was irradiated near 5 and 77 °K with electrons having incident energies between 0.46 and 1.30 MeV. The recovery of the electrical resistivity and the Hall coefficient upon annealing from 4 to 520 °K was monitored. Changes which occurred upon annealing below 200 °K could be reversed by ionizing radiation. A small amount of irreversible ionization-induced recovery was observed after irradiation near 5 °K. Major irreversible recovery stages were centered near 235 (stage I), 280 (stage II) and 520 °K (stage III). Recovery in stage I and II obeyed first order kinetics. The activation energies of stages I and II were determined as 0.72 and 0.83 eV, respectively. The carrier concentration changes per unit irradiation dose corresponding to the three recovery stages differed in their energy dependence indicating that the defects which are removed in stage III have the lowest threshold energy. The carrier concentration changes per unit irradiation dose corresponding to stages I and III ...
81 citations
TL;DR: The microstructural defects produced in molybdenum by neutron irradiation in the temperature range 50 °C to 800 °C have been characterized by transmission electron microscopy as mentioned in this paper.
Abstract: The microstructural defects produced in molybdenum by neutron irradiation in the temperature range 50 °C to 800 °C have been characterized by transmission electron microscopy. At a low irradiation temperature, 50 °C, a large number of small dislocation loops, presumably interstitial, form within a complex dislocation network. At intermediate temperatures, 400–600 °C, small interstitial loops agglomerate into rafts. At high temperatures, 600–800 °C, the small loops which comprise a raft are sufficiently mobile to form large loops which interact with each other to produce a coarse dislocation network. The migration of small loops through the lattice by a combination of prismatic glide and conservative climb accounts for the observed microstructures. Vacancy loops are the only identifiable vacancy defects at temperatures ≥ 500. Between 575–650 °C, both vacancy loops and voids exist. Above 650 °C to at least 800 °C, voids are the exclusive vacancy defect. Information on the effect of impurities and g...
81 citations
TL;DR: In this paper, the migration of defects, leading to eventual reaction, is analyzed on the basis of diffusion theory and compared with chemical rate theory, and a diffusional treatment is carried out in detail and in special cases of particular interest.
Abstract: The migration of defects, leading to eventual reaction, is analyzed on the basis of diffusion theory and compared with chemical rate theory. A diffusional treatment is carried out in detail and in special cases of particular interest. Correlations between interstitials and vacancies, typical of metals following electron irradiation, are examined. Trapping by impurities and dislocations, thermal conversion, and high temperature bombardment are also treated. In each case, formulations are developed along both one- and three-dimensional diffusion models. These alternative results are compared with experiments, particularly annealing in copper irradiated by electrons at low temperature. The results support the conclusion that the defect which migrates in Stage I diffuses in three dimensions.
72 citations
TL;DR: In this paper, the authors used both scanning and transmission electron microscopy (TEM) to investigate the structural damage caused by annealing of implanted silicon, including dislocations, rod-like structures, micro-twins, semi-polycrystalline material, misoriented zones, etc.
Abstract: Silicon specimens were irradiated with Ne+, B+, P+ and Sb+ ions. The energy was 80kV, and the doses in the range 1013 to 1016 ions/cm2. The resulting structural damage was investigated by both scanning and transmission electron microscopy. The SEM electron channelling pattern method was used to determine the variation of gross damage with ion type, dose, depth below the surface, and annealing treatment. The TEM method was used to study the detailed nature of the defects formed by the annealing. These included dislocations, rod-like structures, micro-twins, semi-polycrystalline material, misoriented zones, etc. The results are briefly compared with known electrical properties of implanted silicon, and some correlations noted.
71 citations
TL;DR: In this paper, a new method is presented for the sensitization of plastic track detectors, which consists of irradiating plastics with ultraviolet radiation, UV, in the presence of oxygen, and it has been found effective for cellulosics, polycarbonates, and polyesters.
Abstract: A new method is presented for the sensitization of plastic track detectors. It has been found effective for cellulosics, polycarbonates, and polyesters. Most of the reported data deals with Lexan. The method consists of irradiating plastics with ultraviolet radiation, UV, in the presence of oxygen. The sensitivity enhancement is found to increase exponentially with decreasing UV wavelength and increasing particle restricted energy loss rate, REL. This technique can be used to provide a continuously variable sensitivity from sample to sample, within a given sample, or from one etch to the next of a given sample. Greater spatial resolution is possible because of the increase in the ratio rT/rB. Better charge resolution is possible because of the stronger dependence of the track etch rate, rT, on REL. Long term measurements show that samples stored in the dark in the O2 atmosphere show a small increase in rT with time. In inert atmospheres a negligible increase is observed, and in a vacuum rT decreases.
TL;DR: In this article, a fit between the theoretical and experimental values of displacement cross section was achieved with an effective threshold energy of 28 eV, yielding 35 × 10−4 Ω-cm/fractional concentration for the Frenkel resistivity.
Abstract: Resistivity change as a function of electron irradiation near 8 °K and of annealing after irradiation has been measured on zirconium. Damage rates were measured as a function of incident electron energy from 0.70 to 1.9 MeV. A value of 24 eV for the displacement threshold energy was determined by extrapolation of the damage rate curve to zero damage production. A fit between the theoretical and experimental values of displacement cross section was achieved with an effective threshold energy of 28 eV, yielding 35 × 10−4 Ω-cm/fractional concentration for the Frenkel resistivity. The damage-rate curve indicates no tailing due to subthreshold displacements. Recovery in Zr is analogous to that of fcc and bcc elements studied, but with six substages in Stage I. Substage If (analogous to I e in other materials) was analyzed by using the serpentine plot, which gives an indication of long-range migration of an interstitial between 120 and 150 °K, with an activation energy of 0.26 eV (second order kinetics...
TL;DR: In this article, an integral equation for the pair correlation function, coupling the individual ion range with the deposited energy, was established to determine the damage caused by all those ions that come to rest at a specific penetration depth.
Abstract: Simple depth distribution functions of ion bombardment damage predict the spatial extension of the cumulative damage caused by a beam of ions. Correlation functions need to be considered when more detailed information is desirable, such as the average size or depth of individual damage clusters, the average location of an ion within its damage cluster, and the fluctuations of these quantities. In this paper we establish an integral equation for the pair correlation function, coupling the individual ion range with the deposited energy. This pair correlation function determines the damage caused by all those ions that come to rest at a specific penetration depth. Solutions of the integral equation are found by standard methods. Explicit results are presented for elastic scattering governed by power cross sections. The depth distribution of damage clusters turns out to be significantly narrower than the gross damage distribution at all mass ratios except for M 1 ≪ M 2, and the size distribution appe...
TL;DR: In this article, a Monte Carlo technique was used to move the defects in correlated random walks on a bcc lattice, and a computer simulation of short term annealing of 5- and 20-keV displacement cascades in α-iron has been carried out.
Abstract: A computer simulation of short term annealing of 5- and 20-keV displacement cascades in α-iron has been carried out. A Monte Carlo technique was used to move the defects in correlated random walks on a bcc lattice. Correlations extended to 10th neighbors for interstitials and 5th neighbors for vacancies. A low temperature simulation permitted only interstitial migration, whereas a high temperature simulation permitted both interstitial and vacancy migration with a jump frequency ratio of 100 to 1. Temperature sensitive parameters included the jump frequency of the di-interstitial relative to the single interstitial and the recombination region for unlike defects. Annihilation amounted to 80 per cent and 50 per cent at high and low temperature, respectively. Relative to the low temperature anneal, the high temperature anneal resulted in about the same number of vacancy clusters (although the production of large clusters was clearly enhanced) and only one-third as many interstitial clusters. A deta...
TL;DR: In this article, the crystallinity of ion-implanted silicon has been investigated using ion mass and ion fluence dependences of divacancy formation as measured by the characteristic 1.8 μ absorption band.
Abstract: The crystallinity of ion-implanted silicon has been investigated using ion mass and ion fluence dependences of divacancy formation as measured by the characteristic 1.8 μ absorption band. Room temperature, nonchanneled implants of 400-keV B11, Zn64, and Sb121 ions were performed to maximum fluences of 1014 ions/crn2 for Sb and Zn and to 2 × 1015 ions/cm2 for B. The results are interpreted on the basis of ion energy spent in atomic processes per unit volume, e, within the implanted layer. For e ≤ 1019 keV/cm3 the energy to form a divacancy (1.5 ± 0.5 keV) is nearly ion independent. Maxima appear in the divacancy densities at ∼1013 Sb ions/cm2 and ∼2 × 1013 Zn ions/cm2 where e ≤ 1020 keV/cm3. The divacancy density for B implantation did not exhibit a distinct maximum at E = 1020 keV/cm3, but continued to increase with fluence. The B results are attributed to defect motion because divacancies are observed beyond the calculated depth for energy deposition after a high fluence B implant. In addition t...
TL;DR: In this paper, a high exposure dosimeter based on the relationship between the absorbed dose and the increased chemical reactivity of these dielectric solids is proposed, which can be used to measure absorbed dose in the range of about 107-109 rads.
Abstract: Dielectric plastics are being developed as high exposure dosimeters. The principle of operation is based on the relationship between the absorbed dose and the increased chemical reactivity of these dielectric solids. Polycarbonate plastics can be utilized in measuring absorbed dose in the range of about 107-109 rads. The advantages of the technique lie in the low cost of the detectors, ease of data readout, and high degree of reproducibility achievable. It is hoped that the method can be extended to include the dosimetry of massive doses of soft, low penetrating power X- or γ-radiations.
TL;DR: In this paper, a dilute chemical etch has been employed in conjunction with differential Hall effect measurements to obtain accurate profiles of carrier concentration and mobility vs. depth in conductive implanted layers.
Abstract: Work is described in which chromium-doped semi-insulating gallium arsenide has been successfully doped n-type with ion implanted silicon and sulfur, and p-type with ion implanted carbon. A dilute chemical etch has been employed in conjunction with differential Hall effect measurements to obtain accurate profiles of carrier concentration and mobility vs. depth in conductive implanted layers. This method has so far been applied to silicon-and sulfur-implanted layers in both Cr-doped semi-insulating GaAs and high purity vapor grown GaAs. In the case of sulfur implants, a strong diffusion enhancement has been observed during the annealing, presumably due to fast-diffusing, implantation-produced damage. Peak doping levels so far obtained are about 8 × 1017 electrons/cm3 for silicon implants and 2 × 1017 electrons/cm3 for sulfur implants. Mobility recovery has been observed to be complete except in regions near the surface which are heavily damaged by the implantation.
TL;DR: In recent years, in a number of laboratories throughout the world, a considerable amount of effort has gone into the development and the understanding of organic nuclear charged particle track detectors as discussed by the authors.
Abstract: In recent years, in a number of laboratories throughout the world, a considerable amount of effort has gone into the development and the understanding of organic nuclear charged particle track detectors. Even in their developmental stage these detectors have found numerous applications in several scientific fields. The object of this paper is to present a brief resume of some of the most important recent developments in this field. The scope is limited to the pre-etching phenomena; etching and post-etching treatments are covered by Medveczky.(1)
TL;DR: In this article, the van der Pauw-Hall effect and sheet resistivity measurements were carried out for anneal temperatures ranging from 1100 to 1800°C, and the p-n junction formed by the donor-implanted layers were evaluated as a function of annealing temperature.
Abstract: n-type conducting layers have been formed in n- and p-type hexagonal SiC and n-type cubic SiC by implanting ions from column V of the periodic table; N, P, Sb, or Bi. The implantations were made at room temperature and with energies ranging from 5 to 300 keV. The implanted layers have been evaluated by van der Pauw-Hall effect and sheet resistivity measurements and by scanning electron microscopy for anneal temperatures ranging from 1100 to 1800°C. Type conversion of the implanted layers to n-type has been observed after a 750°C anneal. Considerable lattice reordering is suggested from the observed carrier mobility values after annealing at 1600°C. We have attempted to form p-type layers in n-type SiC by implanting Re, B, Al, Ga, and Tl. Application of anneal procedures identical to those used to form n-type layers have not resulted in measurable p-type layers. The p-n junctions formed by the donor-implanted layers have been evaluated as a function of anneal temperature. After annealing at 1200°C...
TL;DR: In this article, a number of 1ω cm n-type silicon substrates have been implanted with boron at room temperature, and samples from these substrates were annealed at predetermined temperatures between 600°K and 1400°K.
Abstract: A number of 1ω cm n-type silicon substrates have been implanted with boron at room temperature. Samples from these substrates were annealed at predetermined temperatures between 600°K and 1400°K and four-probe electrical measurements and transmission electron micrographs were taken. An attempt has been made to correlate the two studies and it is possible to explain the observed annealing behaviour in terms of precipitation during recrystallization, and migration of defects.
TL;DR: In this article, the yield of scattered 1.8 MeV 12C-ions was studied as a function of the angle of incidence of a beam entering parallel to a (110) direction.
Abstract: Silicon single crystals were implanted under various conditions with Zr, Hf, Tl, and Hg. The yield of scattered 1.8 MeV 12C-ions was studied as a function of the angle of incidence. Around the (111) direction the normal channeling dip was observed. Around the (110) direction either a narrow peak or a narrow peak superimposed on a channeling dip was found. The occurence of the peak is interpreted as being caused by scattering from impurity atoms located in the tetrahedral interstitial holes in the silicon lattice. For a beam entering along a (111) direction these atoms are screened, but they are fully exposed to a beam entering parallel to a (110) direction. The implications of this effect to earlier measurements of the lattice location of impurity atoms in silicon and germanium will be discussed. A similar effect has recently been observed at the University of Aarhus.(6)
TL;DR: In this paper, the degradation of polyethylene and polyoxymethylene crystals in the high voltage electron microscope was determined from 100-1000 kV, assuming that the damage rate is proportional to the ionization rate.
Abstract: The degradation of polyethylene and polyoxymethylene crystals in the high voltage electron microscope was determined from 100–1000 kV. As in previous work at lower electron energies, the dose needed to change the initial crystalline diffraction patterns into amorphous ring patterns was measured. It was found that the dose required to destroy the crystal order increases by a factor of about three in going from 100 to 1000 kV. The result agrees roughly with the theoretically predicted ionization rate, assuming that the damage rate is proportional to the ionization rate.
TL;DR: In this paper, experiments on deuterium bombardment of nickel have been continued and measurements of gas release during and after bombardment have been compared, consistent with the hypothesis that gas release from the solid is controlled by radiation damage sites produced by the incident ions slowing down in the metal.
Abstract: Experiments on deuterium bombardment of nickel have been continued and measurements of gas release during and after bombardment have been compared. The results are consistent with the hypothesis that gas release from the solid is controlled by radiation damage sites produced by the incident ions slowing down in the metal. The population of these damage sites as a function of incident ion dose has been deduced.
TL;DR: In this paper, the sputtering efficiency of graphite, aluminum, silicon, copper, silver, tantalum, and lead with 30-75 keV He+, C+, Ne+, Ar+, Cu +, Kr +, Xe+, and Pb+ ions at perpendicular incidence was measured.
Abstract: The sputtering efficiency (i.e. the ratio of reflected to incident energy) has been measured for graphite, aluminum, silicon, copper, silver, tantalum, and lead with 30–75 keV He+, C+, Ne+, Ar+, Cu + , Kr + , Xe+, and Pb+ ions at perpendicular incidence. The measured efficiencies range from 0.5 per cent (He+ → Si) to 7 per cent (Ne+ → Pb). In accordance with theory, the results for heavier projectiles may be represented as a function of the ratio of target-to-projectile masses M 2 /M 1 only. The results are either energy independent or they decrease with increasing energy, the energy dependence being more pronounced the lighter the targets and projectile.
TL;DR: In this paper, a theory of correlated diffusion annealing is presented which takes into account the trapping of mobile interstitials at impurity atoms, in both the cases of three dimensional diffusion and one dimensional crowdion diffusion.
Abstract: A theory of correlated diffusion annealing is presented which takes into account the trapping of mobile interstitials at impurity atoms. Both the cases of three dimensional diffusion and one dimensional crowdion diffusion are considered. In the case of three dimensional diffusion the trapping can be approximately described by a ‘trapping constant’ in the diffusion equation of the interstitial. To derive this description from the general equations we have used the superposition approximation in which third order correlations are replaced by products of second order correlations. Comparison with experimental data of Sosin and Neely(1) on Au atoms in Cu seems to support the picture of three dimensional diffusion and yields a trapping volume around Au atoms in Cu of about 90 atomic volumes. But from the few data points available no definite conclusions can be drawn concerning the nature of interstitial migration at low temperature.
TL;DR: In this article, the defect annealing time at the threshold of the crystalline to amorphous transition at 173°K for 1 μA/cm2 was calculated for the Si divacancy, following room temperature and 85°K implants of 400-keV B11 or Sb121 ions.
Abstract: Recent results have reported a strong implantation-temperature dependence between 125°K and room temperature for lattice disorder produced by 200-keV B implantation into Si. Using our previous annealing model incorporating implant temperature and dose rate, we have calculated a characteristic defect annealing time at the threshold of the crystalline to amorphous transition at 173°K for 1 μA/cm2 and find that it agrees very closely with that for neutral vacancy annealing. In addition, we have made measurements of the 1.8μ infrared absorption band, characteristic of the Si divacancy, following room temperature and 85°K implants of 400-keV B11 or Sb121 ions. Very few divacancies are observed immediately after 85°K implants, but annealing growth of divacancies occurs between 150 and 300°K yielding a density almost equal to that for the same ion Ruence at 300°K. These results strongly suggest that below 300°K neutral vacancy motion and trapping control both the implantation-temperature dependence of l...
TL;DR: In this paper, the 14.4 keV Mossbauer emission conveys information regarding the chemical forms in which the daughter iron-57 is ‘stabilized’ within 10−7 sec following electron capture.
Abstract: The electron-capture decay of a cobalt-57 atom triggers an Auger event resulting in the loss of several electrons from the molecule in which it is incorporated. The 14.4 keV Mossbauer emission conveys information regarding the chemical forms in which the daughter iron-57 is ‘stabilized’ within 10−7 sec following electron capture. During this time the electronic relaxation occurs completely and several tens of electron volt energy is deposited in the molecule as a result of neutralization. We find that the ethylenediamine tetra-acetate, bis-salicylaldehyde tri-ethylenetetramine, acetylacetone, and indenyl chelates fragment in a large majority of events, resulting in the formation of degraded ionic Fe2+ and Fe3+ in the former cases and C9H7Fe+ in the latter. On the other hand, highly conjugated compounds such as cobalt phthalocyanine and Vitamin B12 escape fragmentation in 100 per cent of the Auger events. Tris-dipyridyl Co(III) perchlorate also escapes fragmentation in a majority of events. Appare...
TL;DR: In this article, the enhancement of diffusion by neutron irradiation has been investigated on a Cu-36 percent Zn alloy for various neutron fluxes and irradiation temperatures by means of in-pile measurements of electrical resistivity.
Abstract: The enhancement of diffusion by neutron irradiation has been investigated on a Cu-36 percent Zn alloy for various neutron fluxes and irradiation temperatures by means of in-pile measurements of electrical resistivity. For fresh samples the diffusion rate depends on temperature with an activation energy of 0.35 eV. During repeated irradiations the diffusion rate decreases and becomes nearly temperature independent. The variation of the concentration of interstitials and vacancies with irradiation time has been numerically calculated for various neutron fluxes, irradiation temperatures and sink concentrations. A comparison of the experimental and theoretical results shows that the point defects annihilate in fresh samples mainly by pair recombination and in samples which had been repeatedly cycled by pair recombination and at fixed sinks. Point defect clusters acting as sinks are created during the course of the irradiation as shown by electron microscope investigations. The radiation enhanced diff...
TL;DR: In this paper, the van der Pauw-Hall technique was used to measure the electrical properties of cadmium, zinc, and sulfur ion-implanted layers in gallium arsenide.
Abstract: The electrical properties of cadmium, zinc, and sulfur ion-implanted layers in gallium arsenide have been measured by the van der Pauw-Hall technique. Ion implantation was performed with the substrates held at room temperature. The dependence of sheet resistivity, surface carrier concentration, and mobility on ion dose and on post-implantation anneal temperature was determined. In the case of 60 keV Cd+ ions implanted into n-type substrates, a measurable p-type layer resulted when samples were annealed for 10 minutes at a temperature in the range 600—900°C. After annealing at 300—900°C for 10 minutes, 100 per cent electrical activity of the Cd ions resulted for ion doses ≤ 1014/cm2. The properties of p-type layers produced by implantation of 85 keV Zn+ ions were similar to those of the 60 keV cadmium-implanted layers, in that no measurable p-type behavior was observed in samples annealed below a relatively high temperature. However, in samples implanted with 20 keV Zn+ ions a p-type layer was obs...
TL;DR: In this article, the ion implantation behavior of three common semiconductor materials, including Si, Ge, and GaAs, was investigated at energies of 40 or 500 keV and doses between 1011 and 2 × 1016 ions/cm2.
Abstract: The present study contributes some new aspects to the general understanding of the ion implantation behaviour of 3 common semiconductor materials, and of diffusion processes in these materials. Single crystals of Si, Ge, and GaAs were bombarded with Kr- or Xe-ions at energies of 40 or 500 keV and doses between 1011 and 2 × 1016 ions/cm2. Gas release measurements and Rutherford scattering of 1 MeV He+-ions combined with channeling were used to study bombardment damage (amorphization) and inert gas diffusion. At low bombardment doses (1011 ions/cm2) and energy (40 keV), no damage was observed and the gas release was compatible with volume diffusion resembling Group I and VIII behaviour. Hence, the pre-exponential terms, D 0, were low (range 10-5±1 cm2 sec−1) and the activation enthalpies, Δ H, were much lower than those of self-diffusion or of diffusion of Group III and V elements. The Δ H's for gas diffusion followed the relation Δ H = (1.05±0.1) × 10−3 Tm eV with the melting point, Tm , in °K. Th...