摘要:

InxGa1−xAs with In composition up to 0.69 has been successfully grown on Si substrates by molecular‐beam epitaxy (MBE) using a modified two‐step and short‐period superlattice process. Double‐crystal x‐ray diffraction revealed a large residual anisotropic strain in samples containing less than 40% In. The short‐period superlattices were effective in reducing dislocations generated near the InxGa1−xAs/Si interface when the In composition was below 0.5.

ISSN:1071-1023    

DOI:10.1116/1.584822

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

The results of a study of the effects of substrate misorientation andexsituthermal annealing on the morphology, defect density, and low temperature photoluminescence (PL) emission of epitaxial films of InP grown on Si substrates are presented. InP films were grown by gas‐source molecular beam epitaxy on both (100) oriented and (100) misoriented 4° towards the [011] Si wafers. InP films on misoriented substrates were mirror‐like over the entire 3‐in. wafer and exhibited a factor of 2 lower dislocation density than films on oriented substrates, as determined by double crystal x‐ray diffraction and transmission electron microscopy (TEM). Thermal annealing resulted in a significant enhancement of the low temperature near band edge PL emission and a decrease in the density of dislocations and stacking faults. The best results obtained were for annealed films on misoriented substrates with an x‐ray linewidth of 440 arcsecs, a TEM dislocation density of ∼2×108cm2, a stacking fault density of ∼2×107cm−2, and a PL linewidth of 6 meV.

ISSN:1071-1023    

DOI:10.1116/1.584823

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

Apparent oscillations in surface temperature occur during the deposition of heteroepitaxial structures when measured using a narrow optical bandpass pyrometer. The oscillation period can be related to the growth rate of the material being deposited, and provides a convenient method for rapidinsitucalibration. For Ga1−xAlxAs alloys the oscillation periods can be directly related to the alloy composition. The pyrometer optics can also be used in conjunction with external light sources so that simultaneous pyrometry and reflectrometry can be carried out at multiple wavelengths.

ISSN:1071-1023    

DOI:10.1116/1.584824

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

The antimony incorporation rate α(Sb) during molecular beam epitaxy (MBE) of GaAs1−ySby, AlAs1−ySby, and Al0.5Ga0.5As1−ySbyis determined as a function of growth conditions via mass‐spectrometric measurements of the nonincorporated fraction of the incident antimony flux. The observed trends of an increase in Sb incorporation rate with decreasing substrate temperature and increasing group III flux, and an increase in resulting Sb content with Sb flux, are found to be in agreement with previous studies usingexsitutechniques only. Additionally, the process of GaAsSb on GaAs interface formation is shown to result in a time dependent α(Sb) and is understood on the basis of a surface Sb‐content dependent Sb desorption rate. Similarly, the Sb desorption rate is found to be time dependent when an incoming Sb flux reacts with a growth interrupted GaAs surface to form a GaAsSb surface layer which is likely to be graded in composition.

ISSN:1071-1023    

DOI:10.1116/1.584825

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

We have studied the surface structures of GaSb, AlGaSb, and alternating GaSb/AlSb layers using 10‐kV reflection electron diffraction. Above 540 °C, the Sb‐stabilized surface (1×3) patterns change toc(8×2), a Ga‐stabilized surface. Because thec(8×2) surface has been observed on all other III–V arsenides, phoshpides, and antimonides, it is now clear that thec(8×2) metal‐stabilized surface is common to all III–V compounds, suggesting that bond pairing occurs on all III–V semiconductor surfaces and is a universal reconstruction mechanism. The smooth, sharp transitions observed in the growth of alternating GaSb and AlSb layers show that atomically smooth interfaces can be formed in this system. In contrast, for the AlAs overgrowth on GaAs, transient structures associated with a Ga surface layer can be observed.

ISSN:1071-1023    

DOI:10.1116/1.584826

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

The intensities of several reflection high‐energy electron diffraction (RHEED) beams have been recorded during molecular‐beam epitaxial growth of GaAs(100) using a novel video intensity measurement system that records multiple RHEED beam intensities simultaneously. The RHEED beam intensities were recorded at varying angles of incidence and crystal substrate azimuth angles. Strong oscillations in the intensities in specular and nonspecular beams with the same period but varying phases have been measured. As noted by other investigators, the phase relationship of the oscillations of the various beams has been found to vary with incident and azimuthal angle. The results are examined with regard to recent studies of the role of Kikuchi processes on the phase of the specular beam. In contrast to other reports, it is found that although the diffracted intensities in the vicinity of the elastically diffracted beams are influenced by inelastically scattered electrons from the Kikuchi lines, these effects can not account for all the phase behavior observed.

ISSN:1071-1023    

DOI:10.1116/1.584827

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

Using a narrow‐bandwidth, short‐wavelength (0.94 μm) pyrometer, we have observed apparent temperature oscillations during molecular‐beam epitaxy (MBE) growth of III–V heterostructures, due to optical interference between different heterostructure layers. These observations confirm the results of SpringThorpe (Refs. 1 and 2) for GaAs and AlAs growth, which indicate that simple interferometric techniques can be used as an alternative to reflection electron diffraction (RED) oscillation techniques for accurate,insitumeasurements of growth rate. We have also measured temperature changes in the growth of lattice‐mismatched (In,Ga)As and InAs, for which RED oscillation techniques are more difficult. For In0.2Ga0.8As growth on GaAs at 500 °C, we observe strong oscillations, with a gradual increase in the average temperature. For InAs growth on GaAs, the indicated temperature rises approximately 60 °C during the first 1000 Å of growth and shows only small, strongly‐damped temperature oscillations. Using the InAs ‘‘congruent evaporation’’ temperature as a reference, we find that most of the rise in indicated temperature is real, even though a proximate back side thermocouple shows only a small temperature change and the substrate heater power is held nearly constant.

ISSN:1071-1023    

DOI:10.1116/1.585054

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

We report a study of growth kinetics of metalorganic molecular‐beam epitaxy (MOMBE) of GaAs by reflection high‐energy electron diffraction (RHEED) intensity oscillation and characterization of these MOMBE‐grown GaAs layers by Hall effect measurement and x‐ray rocking curve analysis. The growth rate depends not only on the substrate temperature but also on the arsenic pressure. The highp‐type doping by carbon, in the high 1019‐cm−3range, results in strain and a smaller lattice constant in the epitaxial layer. Rapid thermal annealing, however, can improve the crystalline quality of the layer without degrading the electrical properties.

ISSN:1071-1023    

DOI:10.1116/1.585055

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

GaAs has been grown by molecular‐beam epitaxy on both silicon and silicon on sapphire. The incorporation of a low temperature buffer has reduced the film stress from 3.0 to 2.2 kbar for GaAs grown on silicon. However, films stress can be completely removed for growth of GaAs with the incorporation of the low temperature buffer when grown on silicon on sapphire (SOS). The orientation dependence of GaAs grown on SOS has been investigated by growing on orientations slightly off axis from the (100) in the [011] direction by 2°, 4°, and 6°. X‐ray, mobility and photoluminescence measurements have been made, showing that growth on 6° misoriented SOS produces nearly stress free films, with materials properties similar to those of GaAs on silicon, and mobilities six times higher than those of GaAs grown on on‐axis (100) SOS. Metal–semiconductor field effect transistors (MESFETs) have been fabricated on GaAs on silicon showing device characteristics comparable to those of GaAs on GaAs.

ISSN:1071-1023    

DOI:10.1116/1.585056

出版商:American Vacuum Society    

年代:1990

数据来源: AIP

摘要:

We present a novel technique for molecular‐beam epitaxy (MBE) growth of InyGa1−yAs/InzAl1−zAs heterostructure field effect transistor (FET) material on GaAs (100) substrates, referred to as metamorphic InyGa1−yAs/InzAl1−zAs HFETs. This new approach uses an InyGa1−yAs step‐graded buffer layer grown at low substrate temperature to accommodate lattice mismatch and to localize misfit dislocations below the active HFET device region grown at standard temperatures. Metamorphic InyGa1−yAs/InzAl1−zAs HFETs grown with a range of compositions (0.25

ISSN:1071-1023    

DOI:10.1116/1.585057

出版商:American Vacuum Society    

年代:1990

数据来源: AIP