Substitutional gold in Si1−xGex

It is demonstrated that relaxed Si1−xGex of 0≤x≤0.25 grown by molecular beam epitaxy, using the compositional grading technique, can be doped with gold by a high-temperature indiffusion process from a deposited gold layer. Substitutional gold in both p- and n-type alloy layers has been identified and characterized by deep level transient spectroscopy, and the donor and acceptor levels of neutral, substitutional gold in the SiGe alloys were studied as a function of the Ge content. The data suggest that both the donor and acceptor levels are pinned to the conduction band.