Graded index silicon geranium on lattice matched silicon geranium semiconductor alloy

US7514726B2 · kind B2 · utility

Assignee

• The United States of America as represented by the Aministrator of the National Aeronautics and Space Administration · US

Inventors

• Yeonjoon Park · Yorktown, US
• Sang H. Choi · Poquoson, US
• Glen C. King · Yorktown, US
• James R. Elliott · Vesuvius, US
• Diane M. Stoakley · Yorktown, US

Key dates

• Filing date: Mar 21, 2006
• Grant date: Apr 7, 2009
• Expiry date: Jun 10, 2027

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/02532
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

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 Al2O3 substrate such that a <110> orientation of the cubic diamond structure SiGe is aligned with a <1,0,−1,0> 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 Si1-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, (ii) is approximately 0.2777 where the layer of Si1-xGex interfaces with the cubic diamond structure SiGe, and (iii) increases linearly with the thickness of the layer of Si1-xGex.