摘要:

The research conducted by Masao Doyama has been summarized: quenching, positron experiments, positive muon spin relaxation, high temperature field ion microscopy, and computer simulations on point defects.

ISSN:1042-0150    

DOI:10.1080/10420159908229081

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:1042-0150    

DOI:10.1080/10420159908229082

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A review is given of reactions between structural defects and impurities in silicon which can effectively be utilized for the method of defect control in device production technology on the basis of the work of author's group. A theoretical treatment of impurity distribution around a structural defect in thermal equilibrium and experimental observations on dislocation pinning and thermal stability of precipitates formed on various types of structural defects give the general mechanism of impurity gettering at structural defects. Dependencies of the gettering efficiency at structural defects on the species and concentration of impurities, the cooling rate of crystal, and the type of structural defects are demonstrated with Fe and Cu impurities in silicon. The morphology of precipitates of supersaturated impurities formed on dislocations is shown to play an important role in strengthening of silicon wafers.

ISSN:1042-0150    

DOI:10.1080/10420159908229083

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:1042-0150    

DOI:10.1080/10420159908229084

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A survey is given on results of experimental studies of the plastic deformation of icosahedral quasicrystals. In particular this concerns the stress-strain characteristics and the determination of the thermodynamic activation parameters of the deformation process. Investigations of the microstructure of plastically deformed samples by means of transmission electron microscopy yield information on dislocation density, dislocation Burgers vectors and slip systems. In addition, fracture surfaces are investigated by scanning tunneling microscopy. The results are discussed in terms of the cluster substructure of the quasicrystal. In particular, the softening observed in quasicrystals with increasing strain is explained by a reduction of quasicrystal structural and chemical order by the continuous introduction of lattice matching-rule violations during the motion of dislocations.

ISSN:1042-0150    

DOI:10.1080/10420159908229085

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:1042-0150    

DOI:10.1080/10420159908229086

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:1042-0150    

DOI:10.1080/10420159908229087

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A unique advantage of high voltage electron microscopy is the fact that continuous observation of phenomena by a variety of electron microscopy techniques is possible simultaneously with the introduction of point defect. Taking this advantage, fundamental studies to clarify the conditions under which non-equilibrium solid phases can successfully be produced under MeV electron irradiation have been undertaken. In this paper, three of the studies have been reviewed: one is concerned with the electron-irradiation-induced amorphization, the second the electron-irradiation-induced phase decomposition and the last the electron-irradiation-induced foreign-atom implantation.

ISSN:1042-0150    

DOI:10.1080/10420159908229088

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

During his long and illustrious career, Professor Kiritani made many of the most significant and revealing observations regarding the nature of the primary damage state and the fate of the produced defects in irradiated metals and semiconductors. We present a review of recent results of molecular dynamics (MD) and kinetic Monte Carlo (KMC) simulations of defect production and annealing in irradiated metals and semiconductors. The MD simulations describe the primary damage state in two prototypical elemental metals and in one-elemental semiconductor, namely Fe, Au, and Si. These materials were all thoroughly investigated by Prof. Kiritani and his colleagues using neutron irradiation followed by TEM observation, and here we attempt to provide some further understanding of the experimental observations by using atomic-scale computer simulation tools. We describe the production of interstitial and vacancy clusters in the cascades and highlight the differences among the various materials. In particular, we discuss how covalent bonding in Si effects defect production and amorphization resulting in a very different primary damage state from the metals. We also use MD simulations to extract prefactors and activation energies for migration of point defects, as well as to investigate the energetics, geometry and diffusivity of small vacancy and interstitial clusters. We show that in the metals, small interstitial clusters are highly mobile and glide in one dimension along the direction of the Burgers vector. The results for the primary damage state and for the defect energetics and kinetics are then combined and used in a KMC simulation to investigate the escape efficiency of defects from their nascent cascade in metals. We show that in fcc metals Au and Pb at or above stage V the escape probability is approximately 40% for 30 keV recoils so that the freely migrating defect fraction is approximately 10% of the displacement per atom (dpa) standard.

ISSN:1042-0150    

DOI:10.1080/10420159908229089

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

This paper consists of two parts. In part 1, the experimental results of damage evolution of neutron-irradiated Cu and Ni are described. In part 2, results of computer simulations are described with linkage of experimental data to explore the atomistic process of damage evolution. To study experimentally the atomistic processes of damage evolution in neutron-irradiated Cu and Ni in part 1, we prepare two types of specimens for both metals. One is as-received specimen from manufacturer. Another is a residual-gas-free specimen which is prepared by melting as-received metals in highly evacuated vacuum at 10−5Pa. Specimens are irradiated with fission neutrons in the temperature-controlled-irradiation capsule at JMTR (Japan Materials Testing Reactor). TEM (Transmission Electron Microscope) observation shows that the dislocation structure is developed by the aggregation of interstitial clusters in irradiated metals. It is found that the number density of void which are observed in specimens, both as-received and residual-gas-free, that are irradiated to a low fluence such as 5.3 × 1018n/cm2at high temperature of 200°C is the same. This suggests that gas atoms are not responsible for the nucleation of voids at high temperature above 200°C in neutron-irradiated Cu and Ni. There are two characteristic temperatures ofTsftandTvoidfor the formation of stacking fault tetrahedra (sfts) and voids at high temperature, belowTsftonly sft forms and aboveTvoid

ISSN:1042-0150    

DOI:10.1080/10420159908229090

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor