Structural relaxation on growing surface during network formation of a-Si:H and a-SiGex:H by chemical annealing

Investigation was made into the role of long-lived species, i.e., atomic hydrogen and excited states of noble gases in “Chemical Annealing (CA)” in making hydrogenated amorphous silicon (a-Si:H) and a-SiGex:H. Distinctive differences were found between Si and Ge in their behaviour on the growing surface in CA-mode, as follows: (1) atomic hydrogen was mainly used to remove the hydrogen covering the growing surface of a-Si:H, but to passivate dangling bonds (DB) on the surface of a-Ge:H; and (2) ion bombardment with excited noble gases such as Ne + under application of DC bias (negative) caused the difference in hydrogen content (C H at%), tendencies to increase and decrease, respectively.