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Proceedings Paper

Substrate Misorientation Effects On (A1,Ga)As And (Al,Ga)As/GaAs Structures Grown By Molecular Beam Epitaxy
Author(s): Raymond K. Tsui; Gary D. Kramer; J. A. Curless; Marilyn S. Peffley
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Paper Abstract

(Al,Ga)As layers have rough surface morphologies when deposited under certain growth conditions in molecular beam epitaxy (MBE). This leads to poor interfaces between (A1,Ga)- As and GaAs and degraded performance in heterojunction devices. We have observed that by misorienting the substrate slightly from (100), in a manner specific to the growth conditions, smooth (Al,Ga)As layers 3-4 μm thick can be grown at a rate of ≈ 1 μm/h for various AlAs mole fractions, x. Similar conditions for nominal (100) result in a rough, textured morphology. Experiments were carried out using flat substrates of specific misorientations as well as lens-shaped substrates. The lenticular substrates allowed all orientations within 14° of (100) [i.e., out to (511)] to be evaluated in one growth run. Deposition conditions that were varied included x, substrate temperature, and V/III beam flux ratio. Smooth layers obtained using optimal misorientations showed superior optical characteris-tics as determined from low-temperature photoluminescence (PL) measurements. The 4.2K PL spectra of smooth layers exhibit well-resolved exciton-related peaks, and do not have the deeper-level defect-related peaks observed in the spectra of rough layers. Single quantum well structures with A10.3Ga0.7As barriers and a 100 A-wide GaAs well deposited on mis-oriented substrates also have superior optical properties compared to a structure grown on nominal (100). Such findings may have significant implications for the performance of heterojunction device structures grown by MBE.

Paper Details

Date Published: 20 April 1987
PDF: 8 pages
Proc. SPIE 0796, Growth of Compound Semiconductors, (20 April 1987); doi: 10.1117/12.940989
Show Author Affiliations
Raymond K. Tsui, Motorola, Inc. (United States)
Gary D. Kramer, Motorola, Inc. (United States)
J. A. Curless, Motorola, Inc. (United States)
Marilyn S. Peffley, Motorola, Inc. (United States)

Published in SPIE Proceedings Vol. 0796:
Growth of Compound Semiconductors
Robert L. Gunshor; Hadis Morkoc, Editor(s)

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