The physics of the growth mechanisms, characterization of epitaxial structures and device properties of GaAs and other compound semiconductors on Si are reviewed in this paper. The nontrivial problems associated with the heteroepitaxial growth schemes and methods that are generally applied in the growth of lattice mismatched and polar on nonpolar material systems are described in detail. The properties of devices fabricated in GaAs and other compound semiconductors grown on Si substrates are discussed in comparison with those grown on GaAs substrates. The advantages of GaAs and other compound semiconductors on Si, namely, the low cost, superior mechanical strength, and thermal conductivity, increased wafer area, and the possibility of monolithic integration of electronic and optical devices are also discussed.

Gallium arsenide and other compound semiconductors on silicon

In studying, describing, and classifying diatoms, the scanning electron microscope (SEM) has become an indispensable tool for diatom taxonomists (1,2) The diatom surface, composed of organic materials and silica, provides excellent working material for use in scanning electron microscopy when properly preserved and fixed The siliceous cell wall, also called a frustule, is often covered with organic material that can obscure key morphological details if not properly removed prior to viewing with the SEM (3) There are several procedures that will allow diatoms to be stripped of their outer organic coverings while keeping the frustule intact Here, we describe the most common techniques used for SEM analysis of diatoms Whenever possible, we have included slight derivations suggested in the current literature to these classical techniques

Scanning electron microscopy.

Stresses and strains in heterostructures have dominated semiconductor research during the last ten years. We review the theory and experimental work on stresses in III - V semiconductor heterostructures in this paper. First large-area lattice mismatched layers (InGaAs and InGaP layers grown on GaAs or InP substrates) and thermally strained layers (GaAs, GaP and InP layers grown directly on Si) are considered. The stresses in large-area epilayer - substrate structures are easy to model because substrate distortion can be neglected and strain in the epilayer is a simple biaxial tetragonal distortion. Calculated splitting of band edges, modification of bandgaps and shifts of Raman modes show good agreement with experiments. Edges of a stripe relax stress in the stripes and induce stress in the substrate. Since stresses in the stripe and the substrate are coupled, calculation of stresses in stripes and substrates is more involved. Recent finite element (FE) calculations of these stresses are discussed in detail and compared with the approximate analytical models and with luminescence and Raman measurements. FE calculations of stresses in buried quantum wires, stressor-induced quantum wires and quantum dots are also discussed. The results of these calculations are used to determine stability and luminescence of the quantum wires and dots and compared with the experimental results. Finally self-organized quantum dots consisting of islands formed during the 3D growth of InAs layers on GaAs are discussed. A possible explanation of the recent observation that they are formed in vertical columns embedded in GaAs is suggested. .

https://iopscience.iop.org/article/10.1088/0268-1242/11/5/004/pdf

Stresses and strains in epilayers, stripes and quantum structures of III - V compound semiconductors

Rapid thermal annealing (RTA) has been found to significantly improve the crystalline quality of epitaxial GaAs grown on Si (100) substrates. After RTA at 900 °C for 10 s, the percentage of displaced atoms near the GaAs/Si interface, as estimated by Rutherford backscattering/channeling, decreased from 20 to 7%. Photoluminescence intensity (PL) after RTA increased significantly (as much as sixfold in some cases), with the actual increase varying from sample to sample and with annealing conditions. In some cases, the PL intensity after RTA was comparable to the PL intensity obtained from GaAs grown on GaAs substrate under similar conditions. Rapid thermal annealing at 940 °C resulted in a degradation of the PL intensity as compared to annealing at 900 °C. Also, the PL peaks after RTA were found to shift to lower energies by 2–5 meV at low temperatures.

Significant improvement in crystalline quality of molecular beam epitaxially grown GaAs on Si (100) by rapid thermal annealing

We discuss recent advances made in the theory and measurements of stresses and strains in Si‐based heterostructures containing submicron‐ and micron‐size features Several reports on theoretical as well as experimental studies of stresses in the substrates with local oxidation of silicon structures on the surface have been published recently With the advent of GeXSi1−X strained layers and stripes extensive studies of both the stripe and the substrate stresses have also been made Unlike the previous calculations and analytical models, recent finite element (FE) calculations take into account the coupling between the film–substrate stresses without making the approximation that the interface is rigid or that there is no variation of stresses in the stripes in a direction perpendicular to the interface The results of these calculations have been compared with the analytical models and limitations of the analytical models have been pointed out Micro‐Raman measurements of the stresses in the stripes, quant

Stresses and strains in lattice‐mismatched stripes, quantum wires, quantum dots, and substrates in Si technology

Photoluminescence and photoluminescence excitation spectra of GaAs grown directly on Si

Cathodoluminescence scanning electron microscopy studies reveal significant variations in stress across etched patterns of GaAs grown on both InP and Si substrates. The stress in the epilayer is relieved at convex corners and in patterned areas with dimensions on the order of 10 μm. The stress is uniaxial near the edge of a patterned region and changes to biaxial away from the edge, producing nonuniformities in the optical properties of patterned regions.

Stress variations and relief in patterned GaAs grown on mismatched substrates

Luminescence studies of thick (≥5 μm) GaAs epitaxial layers grown on Si substrates reveal regions of nonuniform stress associated with the presence of microcracks. Using cathodoluminescence spectroscopy as a tool for microcharacterization, the magnitude of the stress, derived from the peak positions of the luminescence spectra, is shown to increase gradually as a function of distance from the intersection of two microcracks. The greatest degree of stress relief was found at this intersection.

Stress variations due to microcracks in GaAs grown on Si

Photoluminescence and photoluminescence excitation spectroscopies are utilized to study excitons in GaAs/AlGaAs quantum wells (QW’s) fabricated by molecular beam epitaxy on a GaAs buffer layer grown on a Si substrate. The buffer layer was grown by metalorganic vapor phase epitaxy. The experimental results are understood in terms of a uniform biaxial tension of approximately 3 kbar present in the plane of growth for both the QW’s and the GaAs buffer. An important consequence of the biaxial tension is that for QW’s with well widths larger than ≊15 nm the light‐hole and heavy‐hole subbands cross each other in energy, resulting in a light‐hole exciton energy lower than that of the heavy‐hole exciton, opposite to the case of QW’s grown on GaAs substrates.

C. Jagannath

Papers

Photoluminescence and photoluminescence excitation spectra of GaAs grown directly on Si

Stress variations and relief in patterned GaAs grown on mismatched substrates

Stress variations due to microcracks in GaAs grown on Si

Biaxially stressed excitons in GaAs/AlGaAs quantum wells grown on Si substrates

Stress relief in patterned GaAs grown on mismatched substrates