Mechanism of low-temperature crystallization of amorphous silicon by atomic hydrogen anneal

Amorphous silicon (a-Si) films prepared by catalytic chemical vapor deposit ion method using SiH4 and H-2 gas mixtures are crystallized at temperatures <350 degrees C by annealing in atomic hydrogen, (atomic hydrogen anneal: A HA). Atomic hydrogen was generated by catalytic cracking reaction of H-2 ga s on a heated tungsten catalyzer. The crystalline fraction of a-Si film sam ple increased from 0% to several-tens% by AHA, and at the same time, the sa mple was etched with a rate of several-tens nm/min by AHA. Crystallization and etching by AHA depend on structural properties which are related to pot ential crystallinity in the initial a-Si film samples. (C) 2000 Elsevier Sc ience B.V. All rights reserved.