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Growth of Dislocation Free GaAs Epitaxial Layers

IP.com Disclosure Number: IPCOM000080419D
Original Publication Date: 1973-Dec-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Blakeslee, AE: AUTHOR

Abstract

It is known that a small mismatch strain between a substrate and an epitaxial layer grown upon it, will tend to remove dislocations threading through the substrate by bending them over into the interface plane, thus transforming them into misfit dislocations which serve to accommodate the mismatch. In this configuration, they can run out to the edge of the crystal and disappear. It is also known that this process for eliminating dislocations is most effective when the substrate orientation is in the vicinity of (210). Unfortunately, when (210)-oriented substrates are used in a GaAs vapor growth system, the grown layer surface comes out very rough.

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Growth of Dislocation Free GaAs Epitaxial Layers

It is known that a small mismatch strain between a substrate and an epitaxial layer grown upon it, will tend to remove dislocations threading through the substrate by bending them over into the interface plane, thus transforming them into misfit dislocations which serve to accommodate the mismatch. In this configuration, they can run out to the edge of the crystal and disappear. It is also known that this process for eliminating dislocations is most effective when the substrate orientation is in the vicinity of (210). Unfortunately, when (210)- oriented substrates are used in a GaAs vapor growth system, the grown layer surface comes out very rough. In addition to being undesirable from a device processing standpoint, the surface roughness raises the possibility of additional dislocations being created at the edges of the surface steps.

By performing epitaxial growth upon a curved surface containing all orientations within about 10-15 degrees of (210), it has been shown that some regions of the surface indeed are shiny While the portion corresponding exactly to the (210) direction remains quite rough. Orientations only a few degrees away from the (210) plane serve very nearly as well as exact (210) for the purpose of eliminating dislocations. Thus, if the substrate is oriented 10 degrees off (210) in the direction toward the next nearest (110) plane, but such that the nearest (111) plane is a Ga face, a far smoother...