摘要:

The physical system under study is a bonded semiconductor wafer into which hydrogen ions have been implanted within a planar zone, typical of a configuration used in forming semiconductor-on-insulator compliant substrates by wafer splitting. Under the assumption that splitting is a consequence of crack growth driven by hydrogen gas pressure, a lower bound estimate of the implant density required for large area crack growth is obtained which, for an ideal gas, depends only on the cohesive strength of the material and on temperature. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119219

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

By studying the growth ofCu2Oislands during the initial oxidation stage of Cu(001) within situtransmission electron microscopy, it is found that the dominant mechanism for the growth of three-dimensional islands is surface diffusion of oxygen. However, there exists a non-negligible contribution to the metal oxide growth by another mechanism, probably direct impingement of the oxygen atoms on the oxide island. These results demonstrate the importance of surface conditions in oxidation. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119220

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The annihilation of grown-in defects by hydrogen annealing have been explained as the dissolution of oxygen precipitates, because it has been generally thought that grown-in defects in Czochralski silicon crystals are gigantic oxygen precipitates. However, it is necessary to re-examine the mechanism of the annihilation of the defects by hydrogen annealing, because recently it has been shown that the grown-in defects were voids of octahedral shape. In this letter, a simulation model is presented which describes the annihilation process of void defects by hydrogen annealing. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119221

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

A brilliant synchrotron-radiation beam with a large irradiation area has made it possible to use spectroscopic phase-modulated ellipsometry to monitor vacuum-ultraviolet-excited Si homoepitaxy. We find the crystallinity of Si films grown at 250 °C fromSi2H6depends strongly on the photon intensity. When the photon intensity is higher than a critical value, electronically excited crystallization yields epitaxial Si. At lower intensities, however, the initial epitaxy is terminated halfway by island-shaped regions of polycrystalline Si, which are eventually covered by a uniform nanocrystalline Si overlayer. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119222

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The density of amorphous SiC layers formed by 2 MeVSi+implantation into single-crystalline 6H–SiC was measured by x-ray reflectometry and compared with the results of step height measurements. Reactive ion etching was used to investigate the density as a function of depth. The density of the as-amorphized SiC is about 12&percent; less than that of the crystalline material. Within experimental accuracy, the density reduction is homogeneous across the whole layer thickness. Low-temperature annealing leads to the formation of relaxed amorphous SiC with a density about 7&percent; below the crystalline one. These large density changes are in contrast to results in amorphous Si. They can be explained by the high atomic density of SiC and the chemical disorder in the amorphous state of SiC. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119223

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

We report the result of first-principles calculations on Se &dgr;-doped GaAs and propose a carrier compensation mechanism in the region of high Se concentrations. It is found that introducing Ga vacancies near Se atoms makes the system extremely stable and semiconducting. In the high-concentration region where Se atoms are close to each other, the Se atoms are likely to get together by introducing Ga vacancies and form clusters consisting of three Se atoms and one Ga vacancy. The extra electrons of the Se atoms transfer to the dangling bonds of the Se or As atoms, and become electrically inactive. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119224

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Photoelectrochemical etching of silicon using light assistance of various wavelengths has been studied. As the etching process proceeds, a blueshift is noted in the photoluminescence spectra. However, after a certain period of etching, under a fixed current density, a saturation point is reached, below which no further shift to higher energies is detected. This cutoff point occurs at approximately 2 eV, even if a much higher energy irradiant light source is used during the formation process. These results provide strong evidence for the surface-state mechanism of luminescence and render the pure quantum confinement model unlikely. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119225

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

The temperature dependences of the optical absorption edges of semi-insulating GaAs and InP have been measured from room temperature to 905 °C and 748 °C, respectively, with accuracies of ±1 °C at room temperature and ±5 °C at 900 °C. The temperature dependence of the optical absorption edge is adequately reproduced by an Einstein model although the Varshni model gives an improved fit to the band gap. Finally, the widths of the absorption edges are correlated with ionicity. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119226

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

GaAs quantum wells are simultaneously illuminated with near-infrared (NIR) radiation at frequency&ohgr;nirand intense far-infrared (FIR) radiation from a free-electron laser at&ohgr;fir.Magnetic fields up to 9 T are applied. Strong and narrow sidebands are observed at&ohgr;sideband=&ohgr;nir±2&ohgr;fir.The intensity of the sidebands is enhanced when either&ohgr;sidebandor&ohgr;niris near the onset of NIR absorption in the quantum well, or when&ohgr;firis near the free-electron cyclotron frequency. We attribute these sidebands to four-wave mixing of NIR and FIR photons whose energies differ by more than a factor of 100. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119227

出版商:AIP    

年代:1997

数据来源: AIP

摘要:

Recent transport measurements in GaAs–GaAlAs superlattices under THz radiation show evidence of dynamical localization and electron pumping in the opposite direction to the dc bias in the linear response regime. The ac field induces absorption and emission processes in the multiwell structure which assist the tunnel and which are reflected as new features in the current density. A calculation within the framework of the Bardeen Hamiltonian has been performed to evaluate the tunneling current through the superlattice in the presence of an ac field. By means of this model these new features are reproduced in the current which can be explained in terms of the new induced tunneling channels and of the charge occupation in the wells. ©1997 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.119228

出版商:AIP    

年代:1997

数据来源: AIP