Narrow band gap base heterojunction bipolar transistors using SiGe alloys

Novel low temperature epitaxial growth techniques such as molecular beam epitaxy and low temperature chemical vapor deposition permit the use of pseudomorphic Si1-xGex alloys in silicon technology. The smaller band gap of these alloys allows for a variety of novel band-engineered structures that promise to enhance silicon-based technology significantly. In this brief review, we discuss the growth and properties of pseudomorphic Si1-xGex structures ands then focus on their applications, especially the Si1-xGex base heterojunction bipolar transistor. © 1990.