Low‐temperature silicon epitaxy by low‐energy bias sputtering

Bias sputtering at low energies, i.e., comparable to typical crystal interatomic binding energies, has been utilized to control the kinetics of thin‐film growth. It was found that the crystallographic structures of sputter‐deposited silicon films are drastically changed by the energy of ions incident at the substrate. As a result, formation of high quality epitaxial silicon films on (100) silicon substrates has been realized at such low temperatures as 320–350 °C. At the same time, low‐temperature impurity doping of the epitaxial layer has been also demonstrated. Furthermore, the low‐energy bias sputtering process has made it possible to perform very effective substrate surface cleaning at extremely low temperatures without introducing any damage to the substrate.