INTERFACE STRAIN IN INGAAS-INP SUPERLATTICES

Strain has been measured within (001) oriented OMVPE grown multilayer superlattices consisting of thin As-compound layers in InP and thin P- compound layers in GaAs. From the strain behavior, it is interpreted t hat As rapidly replaces P on an InP surface exposed to AsH3 and P slow ly replaces As on a As-terminated surface exposed to PH,. This results in incorporation of an InAs-like strain in InP whose magnitude depend s on the nature of the As-terminated surface. At growth temperatures a bove 600 degrees C, the strain is equivalent to about one monolayer of InAs; while below 600 degrees C, it is equivalent to two monolayers o f InAs. PH3 interaction with GaAs surfaces is sufficiently slow that G aP-like strain is observed only when deliberate interrupts under PH3 a re introduced. GaP grown on GaAs at 650 degrees C is found to incorpor ate enough residual As to sustain a layer composition of GaAs5P5 over the first several monolayers.