摘要:

The basic equations which govern diffusion-controlled reactions of crowdions (crowdion-vacancy annihilation, conversion of crowdions to dumbbell interstitials by means of crowdion-crowdion collisions, as well as conversion of crowdions at dumbbells and at impurities) are derived. ‘Off-line’ crowdions, which are unable to recombine with their ‘own’ vacancies, as well as ‘on-line’ crowdions, which anneal out preferentially in that way, are taken into account. Approaches to the solution of these equations are presented and compared with those found in the literature. In particular, an expression that was fitted successfully by Frank, Seeger, and. Schottky to the Corbett-Smith-Walker annealing data in stage IEof electron-irradiated copper is rederived from the basic equations as an approximate solution for the regime of uncorrelated recovery. This means that the annealing kinetics in stage IEof electron-irradiated copper may be explained in terms of the conversion-two-interstitial model.

ISSN:0033-7579    

DOI:10.1080/00337577108231021

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

This paper was given as the opening address at the 1970 Albany International Conference on Radiation Effects in Semiconductors, and it attempts to establish a general overview of the field by concentrating on recent research developments and important unanswered questions. The continuing importance of impurity-defect interactions, of microscopic defect identification, and of the necessity for more theoretical calculations are emphasized. The rapid development of the field of ion implantation and its close relationship with radiation effects studies are pointed out. It is predicted that research in compound semiconductors will increase rapidly with close beneficial interaction with ion implantation studies.

ISSN:0033-7579    

DOI:10.1080/00337577108231022

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Lightly dopedn-type Ge, irradiated at liquid He temperatures with 1 MeV electrons, exhibits a large thermal recovery stage at 50–70°K. We have found that the rate at which this stage anneals depends on the type of group V impurity used to dope the sample. We Propose that impurity complexes are involved in this annealing stage. We have also observed the same impurity dependence when this annealing stage is destroyed by radiation annealing at liquid He temperatures. This suggests that one of the defects produced during irradiation is free to migrate at very low temperatures.

ISSN:0033-7579    

DOI:10.1080/00337577108231023

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

We have studied the influence of the nature and concentration of donor impurity on the 65°K and 35°K stages in electron irradiatedn-type germanium. Because the nature of the impurity does not influence the 65°K stage and because this stage is present alone in lightly doped samples, we confirm that it is associated with the annihilation of a vacancy-interstitial pair. Because the 35°K stage is directly connected to the impurity concentration, and not to the free electron concentration, we conclude that it is associated with the annihilation of a vacancy and interstitial-impurity pair. We have shown that the annihilation of the vacancy-interstitial pair occurs through the interstitial mobility at 65°K, 27°K and 4.5°K depending on its charge state, and that the interstitial-impurity mobility occurs at 35°K.

ISSN:0033-7579    

DOI:10.1080/00337577108231024

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Annealing of radiation induced defects inp-type germanium was studied by measuring Hall coefficient and conductivity. The dopant was gallium or indium. It was concluded that the annealing stage between 80° and 140°K is caused by migration of the vacancy to the sink of an impurity atom. In this stage the vacancy migrates to a substitutional impurity atom and makes an association. The activation energy of the stage was found tO be 0.1 ev ad it is regarded to be that of the vacancy migration. The model for the annealing stage which occurs in the range 220 to 270°K is proposed as follows: An interstitial impurity atom migrates to a substitutional impurity atom and makes an association. From the activation energy of the stage, the migration energy of the interstitial impurity atom was concluded to be about 0.4 eV for gallium and 0.7 eV for indium atoms.

ISSN:0033-7579    

DOI:10.1080/00337577108231025

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

A Mössbauer-type structure has been observed in the 15°K spectra of germanium crystals irradiated at room temperature by Co60γ-rays and 700 keV electrons. The spectra consist of an intense band peaking at 0.688 eV accompanied by mainly TA-phonon-assisted lower energy sidebands. The transition producing the luminescence is believed to be the annihilation of an exciton bound to a defect center by forces of shorter range than coulombic attraction. The dependence of the new spectra upon irradiation temperature and certain sample characteristics indicate that the center contains both primary defect(s) and an unknown impurity.

ISSN:0033-7579    

DOI:10.1080/00337577108231026

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Studies of recombination in ∼0.2 Ω-cm As- and Sb-doped Co60γ-irradiated Ge which yield energy levels and the temperature dependence of the electron and hole capture probabilities are reported. For Sb-doped material at 323°K, the recombination center energy level position (neglecting statistical weight) was found to be 0.361±0.005 eV above the valence band with a possible slight temperature dependence corresponding roughly to one-half the variation of band gap with temperature. The capture probability ratio at this same temperature was 740. For the Asdoped case, two different levels appear to dominate the recombination process in annealed and unannealed low resistivity material. The energy level positions relative to the valence band (neglecting statistical weight) are 0.327±0.005 eV and 0.37±0.01 eV at room temperature for the annealed and unannealed samples, respectively. The corresponding capture probability ratios are 650 and 810. As in the case of Sb-doping, the energy level appears to shift with temperature at about one-half the rate of the shift in band gap energy.

ISSN:0033-7579    

DOI:10.1080/00337577108231027

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Irradiation of silicon by 2 MeV electrons at 130°K leads to the removal of carbon from substitutional sites and the formation of centres with axial symmetry having vibrational modes at 921 and 930 cm−1for12C; large isotope shifts are found in crystals containing13C and14C. This centre is considered to involve interstitial carbon atoms but not oxygen impurities. On annealing such irradiated crystals to room temperature the concentration of these centres is reduced and a new transient centre involving carbon has been detected. Further annealing leads to the formation of the well known 11.56μm absorption band in pulled crystals and it is shown that this may be correlated with another band at 1115.5 cm−1. Again large isotope effects are found in crystals containing13C and14C and this centre is ascribed to a [O-C] complex involving an interstitial carbon atom.

ISSN:0033-7579    

DOI:10.1080/00337577108231028

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Fast neutron irradiations of silicon are studied through the cobalt-57 probe incorporated into the lattice.

ISSN:0033-7579    

DOI:10.1080/00337577108231029

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor

摘要:

Using electron paramagnetic resonance (EPR) the identity of the point defects produced by fast neutron irradiation of silicon at room temperature has been determined and the concentration of each defect has been measured. Irradiations were performed at an unmoderated fast burst reactor to assure that damage from gamma irradiation could be neglected and that all the observed damage could be attributed to displacements by fast neutrons. Total fast neutron fluence between 1.2 × 1015n/cm2and 7 × 1015n/cm2was used.

ISSN:0033-7579    

DOI:10.1080/00337577108231030

出版商:Taylor & Francis Group    

年代:1971

数据来源: Taylor