Kinetic Aspects of Lattice Mismatch in Molecular Beam Epitaxial Growth on Planar and Patterned Substrates
Annual technical rept. 1 Feb 90-31 Jan 91,
UNIVERSITY OF SOUTHERN CALIFORNIA LOS ANGELES DEPT OF MATERIALS SCIENCE AND ENGINEERING
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This work focuses on examining the nature of the molecular beam epitaxial growth process, its control and optimization, achieving defect reduction via growth on prepatterned substrates, and the behavior of some optical and transport characteristics for strained system using InGaAsAlGaAs as the vehicle. Highlights include 1 the first demonstration of GaAs111B homoepitaxy free of twins and with mirror-like surfaces through usage of real- time reflection electron diffraction intensity behavior 2 demonstration of the presence of strain in the substrate to unexpectedly large depths below 3D islands of InGaAs 3 presence of atomic relaxation in coherent islands 4 the tendency for defect introduction at island edges beyond a critical size 5 realization of strained InGaAsAlAs resonant tunnelling diodes with room temperature peak currents approximately 125 kAmpsq cm and peak-to-valley ratios of 51 6 defect reduction via strain relief at mesa edges in growth on prepatterned mesas, 7 realization of good electroabsorption in thick 1 to 2 microns strained multiple quantum wells 8 dielectric encapsulation induced strain shifts, and 9 rapid thermal annealing induced intermixing of components at interfaces and the resulting changes in the nature of the quantum well potential.
- Solid State Physics