Amorphization/recrystallization of buried amorphous silicon layer induced by oxygen ion implantation

In this paper we discuss the structural modifications observed in a buried amorphous Si (a-Si) layer containing high oxygen concentration level (up to similar to3 at. %) after being implanted at elevated temperature with O-16(+) ions. For implants conducted at temperatures lower than 150 degreesC, the a-Si layer expands via layer by layer amorphization at the front and back amorphous-crystalline (a-c) interfaces. When performed at temperatures above 150 degreesC, the implants lead to the narrowing of the buried a-Si layer through ion beam-induced epitaxial crystallization at both a-c interfaces. Cross section transmission electron microscopy analysis of samples implanted at 400 degreesC revealed an array of microtwins and a dislocation network band in the recrystallized material. In samples implanted at 550 degreesC, only a buried dislocation network band is observed. (C) 2004 American Institute of Physics.