GRADED INDEX SILICON GERANIUM ON LATTICE MATCHED SILICON GERMANIUM SEMICONDUCTIVE ALLOY

摘要

A lattice matched silicon germanium (SiGe) semiconductive alloy is formed when a {111} crystal plane of a cubic diamond structure SiGe is grown on the {0001} C-plane of a single crystalline Al<SUB>2</SUB>O<SUB>3</SUB> substrate such that a <110> orientation of the cubic diamond structure SiGe is aligned with a <l,0,-l, 0> orientation of the {0001} C-plane. A lattice match between the substrate and the SiGe is achieved by using a SiGe composition that is 0.7223 atomic percent silicon and 0.2777 atomic percent germanium. A layer of Sij,- xGex is formed on the cubic diamond structure SiGe. The value of X (i) defines an atomic percent of germanium satisfying 0.2277<X<1.0, f ii) is approximately 0.2777 where the layer of Si<SUB>1-x</SUB>Ge<SUB>x</SUB> interfaces with the cubic diamond structure SiGe, and (iii) increases linearly with the thickness of the layer of Si<SUB>1-x</SUB>Ge<SUB>x</SUB>.