摘要:

The radiation hardness of metal‐oxide semiconductor capacitors with nitrided oxides prepared by rapid thermal nitridation (RTN) has been studied. The radiation was performed by exposing devices to 50 keV x ray to a dose of 0.5 Mrad (Si). Compared to conventional thermal oxides, the rapid thermal nitrided oxide devices exhibit much less increase in the interface state density (Dit). In addition, it is found that higher RTN temperatures and/or longer durations produce smaller &Dgr;Dit. The significant reduction of the interface state generation has been attributed to the strain relief effect due to the incorporation of nitrogen at the Si/SixNyOzinterface. The bond strain related models have been discussed to explain the results.

ISSN:0003-6951    

DOI:10.1063/1.102446

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

GexSi1−xalloy layers grown on (100) silicon substrates by molecular beam epitaxy and amorphized by ion irradiation at −196 °C are shown to recrystallize epitaxially during subsequent ion irradiation at 275 °C. This ion beam annealing process has been examined for two different sample configurations: the first consisting of a thin amorphous layer extending from the surface to about half the thickness of the alloy layer, and the second consisting of a thick amorphous layer extending beyond the alloy layer into the underlying silicon. In both cases, ion beam annealing results in epitaxial crystallization of the alloy layer. Results are reported for alloy composition in the range from Ge0.1Si0.9to Ge0.8Si0.2.

ISSN:0003-6951    

DOI:10.1063/1.102264

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We report on the use of x‐ray photoelectron spectroscopy for the investigation of radiation damage in GaAs. The technique has been used to profile the damage induced by 7 MeV Si+ions. Arsenic displaced by the ions is found in an interstitial elementary state. Using chemical etching, we are able to trace the distribution of As displacement. The results are in good agreement withtrimcalculations of radiation damage. The potential applications of this technique to the study of the nature and distribution of radiation damage are discussed.

ISSN:0003-6951    

DOI:10.1063/1.101774

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Using Raman scattering we have measured the longitudinal optic phonon energies of Ga1−xInxAs layers with 0.48≤x≤0.55 grown on InP substrates. In order to interpret these data successfully it was necessary to consider the effect of the strain induced by the lattice mismatch. Existing theory has been extended to consider the case of alloy pseudomorphic layers and is approximated to a linear form. This theory is also applied to Ga1−xInxAs on GaAs and compared with previously published data with 0≤x≤0.2. Close agreement between theory and experimental data is found indicating that the Raman technique, combined with this theory, can be used to measure the alloy composition of pseudomorphic strained layers of diamond or zinc blende structure accurately without the need for detailed experimental calibration. It is suggested that this method could be particularly useful for determining the composition of alloy layers in thin layer pseudomorphic Ga1−xInxAs/InP heterostructures.

ISSN:0003-6951    

DOI:10.1063/1.101775

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The reaction between solid layers to form a product phase has been studied using scanning calorimetry of multilayer Nb/Al and Ni/amorphous‐Si thin films. The most striking feature for both materials systems is the occurrence of two maxima in the reaction rate during the formation of a single product phase, suggesting a two step growth process. A model has been developed in which the first step is taken to be the nucleation and two‐dimensional growth to coalescence of the product phase, in the plane of the initial interface. The second step is taken to be the thickening of the product layer by growth perpendicular to the interface plane. The success of this simple model in describing the principal features of the experimental results on two different materials systems suggests that nucleation is an important aspect of phase formation and selection in these thin‐film reactions.

ISSN:0003-6951    

DOI:10.1063/1.102447

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

GaAs/AlGaAs quantum wells (QWs), selectively intermixed by SiO2capping and rapid thermal annealing, have been characterized on a microscale using spatially resolved photoluminescence (PL) spectroscopy. From the evolution of the PL spectra across the boundary between the unmixed and intermixed regions, it was concluded that the transition region is narrower than the 1.5 &mgr;m excitation beam diameter. The magnitude of the intermixing was also found to increase with the thickness of the oxide. The present intermixed QWs were found to be stable against subsequent thermal treatment below the temperature limit imposed by the intrinsic interdiffusion. These results demonstrate that the effective band gap of QWs, and their physical properties, can be adjusted by controlling the oxide thickness profile.

ISSN:0003-6951    

DOI:10.1063/1.101776

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

Pyrolysis of high‐purity digermane (Ge2H6) has been used to grow epitaxial Ge films of high crystalline quality on (100) GaAs substrates in a low‐pressure environment. X‐ray double‐crystal diffractometry shows that fully commensurate, coherently strained epitaxial Ge films can be grown on (100) GaAs at digermane partial pressures of 0.05–40 mTorr for substrate temperatures of 380–600 °C. Amorphous films also were deposited. Information about the crystalline films surface morphology, growth mode, and microstructure was obtained from scanning electron microscopy, cross‐section transmission electron microscopy, andinsitureflectivity measurements. The amorphous‐to‐crystalline transition temperature and the morphology of the crystalline films were both found to depend on deposition conditions (primarily the incidence rate of Ge‐bearing species and the substrate temperature). Epitaxial growth rates using digermane were found to be about two orders of magnitude higher than rates using germane (GeH4) under similar experimental conditions.

ISSN:0003-6951    

DOI:10.1063/1.101777

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The surface chemistry and band bending of the ammonium sulfide‐treated GaAs (100) surface has been studied using surface‐sensitive synchrotron radiation photoemission spectroscopy. We find that the treatment leaves the GaAs surface terminated with roughly a monolayer of sulfur bonded to both As and Ga atoms. Ann‐type barrier height of 0.8 eV is measured. The thermal stability of the various chemical components is studied and various issues of the passivating mechanism are discussed.

ISSN:0003-6951    

DOI:10.1063/1.101780

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

The second energy level of the EL2 defect (EL2+/++) is observed by using the infrared absorption technique and monochromatic light irradiation in undoped and lightly alloyed unannealed bulk GaAs. The EL2+/++spectrum exhibits a complex structure and it does not exist in annealed samples. The EL2+/++→EL20/+and EL20/+→EL2+/++transitions were obtained by illuminating the samples with 0.7≤h&ngr;≤0.95 eV and 1.3≤h&ngr;≤1.5 eV, respectively. The transformation EL2+/++↔EL20/+can be achieved in less than 10 s and can be repeatedly switched back and forth between the two states.

ISSN:0003-6951    

DOI:10.1063/1.101623

出版商:AIP    

年代:1989

数据来源: AIP

摘要:

We show that macroscopic, as opposed to microscopic, steps can be obtained on a semiconductor vicinal surface when a perturbation has been ‘‘printed’’ on it, prior to epitaxial growth. This generic crystal growth concept has been studied here with the GaAs/AlGaAs system using organometallic chemical vapor deposition. The details of step formation, stabilization, and subsequent propagation have been investigated with scanning electron microscopy. Regular, sawtooth‐like growth patterns have been obtained, with periodic growth rate differences at the step edges. This novel lateral patterning technique was employed to fabricate arrays of quantum wire‐like heterostructures.

ISSN:0003-6951    

DOI:10.1063/1.101624

出版商:AIP    

年代:1989

数据来源: AIP