摘要:

New metastable behavior of deep levels is found in hydrogenated GaAs doped with Si. A deep level at 0.60 eV below the conduction‐band minimum (Ec) is generated during hydrogenation and shows metastable for theEc− 0.42 eV trap. From the defect transformations observed in biased anneals, these defects are found to be metastable defects associated with hydrogen atoms. Especially, the 400 K biased‐anneal experiments indicate that anEc−0.33 eV trap could be an electric field induced defect, transformed from other intrinsic defects. TheEc− 0.60 eV trap in hydrogenated GaAs could be a hydrogen complex associated withEc− 0.42 eV trap and the hydrogen atom plays an important role in a metastability of deep level defects in GaAs.

ISSN:0003-6951    

DOI:10.1063/1.105056

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Slow evaporation of In from InP wafers has been investigated and identified as a major cause of surface roughness in thermal annealing and mass transport under sufficient phosphorus vapor protection. An analysis shows that In evaporation can be prevented by covering the wafer during the annealing process. However, the commonly used graphite cover by itself is inadequate protection because In vapor is able to permeate the graphite. On the other hand, InP covers alone result in problems caused by the mass transport that occurs between the InP wafer and cover. A covering scheme has been developed that uses InP covers and a quartz enclosure in addition to the graphite cover. This arrangement provides effective wafer protection permitting smooth wafer surfaces to be obtained reproducibly.

ISSN:0003-6951    

DOI:10.1063/1.105057

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The materials‐related effects due to rapid thermal nitridation and reoxidation of thermally grown SiO2were studied in the underlying silicon. Depth profiles using spreading resistance, auger electron spectroscopy, and secondary‐ion mass spectroscopy are presented to show that enhanced dopant diffusion and surface depletion result from rapid thermal process treatments. Silicon interstitial injection from the nitrogen supersaturated oxynitride interface facilitates the diffusion of boron, phosphorus, and arsenic atoms in the silicon substrate. An appreciable amount of nitrogen was found below the silicon surface, suggesting that nitrogen interstitials may play an important role in the observed enhanced impurity diffusion.

ISSN:0003-6951    

DOI:10.1063/1.105058

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

High quality polycrystalline diamond films have been synthesized in a premixed, turbulent oxygen‐acetylene flame, using a commercial brazing torch. The quality of the films was measured by Raman spectroscopy, electron microscopy, and hemispherical transmittance measurements in the ultraviolet, visible, and infrared. Turbulence was achieved by operating the torch with a sufficiently high Reynolds number. The presence of turbulence was confirmed by observations of changes in the flame shape, the characteristic sound of the flame, and calculation of the Reynold’s number.

ISSN:0003-6951    

DOI:10.1063/1.105059

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

InGaAs/GaAs strained‐layer superlattices have been grown by molecular beam epitaxy and characterized with photoconductivity measurements. The layers were dopedptype by diffusion of Zn in an ohmic contact annealing process. A sudden reduction in room‐temperature photoconductivity of thep‐type samples was observed at photon energies slightly below the GaAs band gap in all of the samples. This spectral feature is proposed to originate from photoionization of acceptor‐like defect states in GaAs, and a model accounting for this phenomenon is discussed.

ISSN:0003-6951    

DOI:10.1063/1.105060

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We investigate the dependence of carrier lifetimes in radiation‐damaged, GaAs on proton implantation dose by means of time‐resolved reflectivity and photoconductivity experiments with subpicosecond resolution. The carrier lifetimes decrease with increasing implantation dose at low implantation levels whereas beyond the ‘‘amorphization dose’’ a saturation at 0.5 ps can be observed due to a saturation of the defect density.

ISSN:0003-6951    

DOI:10.1063/1.105061

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We used 2 MeV4He backscattering spectrometry, x‐ray diffractometry, and the van der Pauw technique to study how epitaxial ReSi2films on Si(100) change structurally and electrically upon room‐temperature implantation of 300 keV28Si or 380 keV40Ar. The as‐grown film has a minimum channeling yield of ∼2% for Re, and a resistivity of ∼23 m&OHgr;cm at room temperature. Ion implantation produces damage in the film, which increases monotonically with dose. At a dose of either 5×101428Si/cm2or 1×101440Ar/cm2, the entire ReSi2film becomes both x‐ray and channeling amorphous. The resistivity of the film decreases monotonically with dose. The amorphous film has a resistivity of ∼1.2 m&OHgr;cm at room temperature. Upon annealing in vacuum at 700 °C for 30 min, the damage anneals out and the amorphous ReSi2film recrystallizes epitaxially, once again exhibiting a minimum channeling yield of ∼2% for Re and a resistivity of ∼23 m&OHgr;cm.

ISSN:0003-6951    

DOI:10.1063/1.105062

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Epitaxial growth of GaAs on Si commonly employs a high‐temperature (≳850 °C) oxide desorption step. In this letter, we report the first epitaxial growth of GaAs on Si without the need for this high‐temperature treatment. This method utilizes a final HF treatment whereby the Si surface dangling bonds are terminated by hydrogen with a resultant (1×1) bulk‐like surface structure. Upon medium temperature heat treatment (×500 °C), hydrogen leaves the surface leading to the common orthogonal 2×1 surface reconstruction. High quality GaAs epitaxial layers were successfully grown on these 2×1 reconstructed Si surfaces with the pregrowth substrate preparation temperatures of as low as 600 °C.

ISSN:0003-6951    

DOI:10.1063/1.105063

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

High spatial resolution Auger electron spectra and images have been obtained by optimizing secondary electron collection efficiency in a scanning transmission electron microscope (STEM). We describe an ultrahigh vacuum, 100 keV STEM which is capable of collecting Auger electron spectra and images with edge resolutions of ≤5 nm. Typical spectra and images from the Ge/Si(100) and Ag/Si(100) film growth systems are presented and discussed. These images demonstrate high‐resolution elemental mapping which can be used in the study of surface processes on the nanometer scale.

ISSN:0003-6951    

DOI:10.1063/1.105064

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The Schottky barrier characteristics of aluminum contacts to In0.05Ga0.95As/GaAs strain‐relieved material were investigated. Acidic and alkaline wet chemical etching experiments were performed to determine the importance of semiconductor surface preparation prior to the deposition of the contact metal. Acidic etch treatments utilizing HCl and HF resulted in a range of ideality factors significantly greater than 1 (1.90–2.91 for HCl, 1.35–2.46 for HF), variable reverse bias leakage currents (0.038–0.440 &mgr;A/cm2for HCl, 23.0–110 &mgr;A/cm2for HF), and a range of barrier heights (0.88–0.93 eV for HCl, 0.63–0.77 eV for HF). In addition, the HCl treated devices exhibit time‐dependentI‐Vbehavior with continuous measurements, as well as changes in characteristics with both annealing and room‐temperature storage. The 10 s NH4OH:H2O (1:1) alkaline etch surface preparation produced stable Schottky contacts with a 0.79 eV barrier height, a 1.15±0.02 ideality factor, and ≊10 &mgr;A/cm2leakage current at −1 V bias.

ISSN:0003-6951    

DOI:10.1063/1.105065

出版商:AIP    

年代:1991

数据来源: AIP