GaAs SUBSTRATE WITH COMPOSITIONALLY GRADED AlGaAsSb BUFFER FOR FABRICATION OF HIGH-INDIUM FETS

摘要

Semiconductor devices made in high-indium-content semiconductor material (16) have advantageous properties, but similar substrate materials are hard to handle. A buffer layer (18) makes a lattice-constant transition between a GaAs substrate and a high-indium epitaxially deposited semiconductor such as those lattice-matched to InP. The buffer layer (18) is an epitaxial layer including atoms of two Group III elements, and atoms of two Group V elements, with the ratio of the atoms of at least one group varied along the depth of the buffer layer, in a manner which makes a transition of the lattice constant between that of the substrate and the high-indium semiconductor material. The Group III elements are gallium and aluminum, and the Group V elements are arsenic and antimony.