摘要:

A defining equation to describe the moments of the surface concentration-eroded depth profile of a marker species during sputter erosion, in the framework of ion bombardment enhanced diffusivity and which includes the process of ion penetration and trapping, is developed. Simplified trapping profiles illustrate the effect of this process in modifying profile moments. Estimates of large erosion depth quasi-exponential decay lengths are also made and, again, the role of ion trapping is elucidated. It is concluded that experimental measurements of these profile parameters (particularly the profile moments for which analysis is rigorous and exact) should be preferably compared with the results developed in this work rather than with previous treatments. The exceptions to this proposal are either when the sputtering yield is much larger than the total ion trapping probability, so that substrate dilation or compression can be ignored, or when it can be definitely assumed that the characteristic length of the diffusion process is much larger than the depth over which diffusion enhancement occurs.

ISSN:1042-0150    

DOI:10.1080/10420159608211504

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The electrical behavior of a diode, either reverse or forward biased, under a radiation pulse, is considered. The variations of the current produced by the diode are explained by the consideration of variable I-V characteristics, showing the different diode behaviors according to the working mode. This approach is then applied to explain some electrical properties of an irradiated transistor.

ISSN:1042-0150    

DOI:10.1080/10420159608211505

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

We determined the increase of the electrical resistivity in copper, Be doped copper, and in gold during irradiation with 1.85 MeV electrons below the temperature corresponding to the stage III recovery region. From the analysis of these data by means of rate equations we are able to determine the variations of the concentrations of interstitials, vacancies and agglomerates of interstitials as a function of the irradiation time and of the irradiation temperature.

ISSN:1042-0150    

DOI:10.1080/10420159608211506

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

An innovative method for device characterization is developed to qualify radiation effects. A study of radiation induced effects on carrier transport phenomena has been carried out on the body-drain junction of power HEXFETs. A large increase of the recombination current is pointed out. The degradation, by ionizing radiation of the junction ideality factor is shown to be controlled by the total dose. These effects are discussed and related to the oxide-semiconductor interface potential.

ISSN:1042-0150    

DOI:10.1080/10420159608211507

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The emission of atoms induced by ion bombardment of a crystalline nickel target was investigated using the collector method: the sputtered atoms condense on the surface of a hemispherical collector placed above the target, and the thickness distribution of the condensed matter, which is a measure of the angular emission distribution, is determined with a modified scanning electron microscope by measuring the backscattered electron ratio with high spatial resolution.

ISSN:1042-0150    

DOI:10.1080/10420159608211508

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The hardening effect on the surface layers of WC–Co alloys after Ar+- and N+-ion implantation with the fluence in the range 1 ÷ 8.7 × 1017cm−2has been investigated at room temperature and under heating with an ion beam. The depth of the Auger distribution profiles and the microhardness of implanted samples were measured. The radiation-stimulated diffusion of nitrogen atoms and the microhardness enhancement were observed. The contribution of the polymorphic Co-phase transformation and the production of Co–N compounds is discussed.

ISSN:1042-0150    

DOI:10.1080/10420159608211509

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:1042-0150    

DOI:10.1080/10420159608211510

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A review is given of the state of the art in one of the current topics in radiation doping of semiconductors, which is process of nuclear transmutation doping (NTD) by charged particles. In contrast to the neutron and photonuclear transmutation doping, which have been dealt with in monograths and reviews, NTD caused by the action of charged particles is a subject growing very rapidly in the last 10–15 years, but still lacking systematic accounts. The review consists of three sections. The first section deals with the characteristics of nuclear reactions in semiconductors caused by the action of charged particles: the main stress is on the modeling of NTD processes in semiconductors under the action of charged particles. An analysis is made of the modeling intended to give the total numbers of donor and acceptor impurities introduced by the NTD process, to optimize the compensation coefficients, and to estimate the distributions of the dopants with depth in a semiconductor crystal. In the second section the state of the art of experimental investigations of NTD under the influence of charged particles is considered. In view of the specific objects that have been investigated experimentally, the second section is divided into three subsections: silicon, III–V compounds, other semiconductors and related materials (such as high-temperature superconductors, ferroelectric films, etc.). An analysis is made of the communications reporting experimental data on the total numbers of dopants which are introduced, concentration of the electrically active fraction of the impurity, profiles of the dopant distributions, and conditions for efficient annealing of radiation defects. The third section deals with the suitability of NTD by charged particles for the fabrication of semiconductor devices.

ISSN:1042-0150    

DOI:10.1080/10420159608211511

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Thermal neutron irradiation produces spatial and energetical homogenously distributed defects in n-GaAs which act as charge carrier traps and scattering centres and as recombination sites for photogenerated charge carriers. Therefore, after neutron irradiation the charge carrier concentration and mobility and the maximum photocurrent are lowered and the photocurrent onset potential is further shifted in positive direction versus flatband potential. Annealing of the irradiated samples leads to defect annihilation and thus, to the recovery of the original electrochemical characteristics. Annealing at temperatures above 600°C leads to an arsenic deficient surface with electronic defect states in the band gap in the near-surface region. Recombination at these defects only influences the maximum photocurrent, but not the photocurrent onset potential.

ISSN:1042-0150    

DOI:10.1080/10420159608211512

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The electron energy spectra of divacancies created by fast neutron radiation have been computed by means of the cluster approach with a combination of the quantum chemical molecular orbital method and the static relaxation process. The computed results were verified by Deep Level Transient Spectroscopy (DLTS) and found to be similar to the numerical data.

ISSN:1042-0150    

DOI:10.1080/10420159608211513

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor