QUANTUM DEVICES USING SIGE/SI HETEROSTRUCTURES

Strained-layer Si1-xGe(x)/Si heterostructures have created a great deal of interest due to the potential of integration with the conventional silicon very large scale integrated technology. With the current advances in silicon molecular beam epitaxy (Si-MBE) and other low-temperature epitaxial techniques, many Si1-xGe(x)/Si heterojunction devices have been realized. For example, among those realized are avalanche photodiodes, modulation-doped field-effect transistors, heterojunction bipolar transistors, and more recently, resonant tunneling structures, hot-carrier transistors, and quantum well metal-oxide-semiconductor field-effect transistors. In this paper, several quantum size effects in strained Si1-xGe(x) layers and their potential in device applications will be reviewed. Among those to be discussed are resonant tunneling, miniband transport, and intersubband absorption in Si1-xGe(x)/Si superlattice structures, optical properties of monolayer Si(m)Ge(n) superlattices, and observation of large Stark effect associated with interband transition between quantized states in Si1-xGe(x)/Si quantum well structures.