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

Abstract

In this paper we discuss the structural modifications observed in a buried amorphous Si (α-Si) layer containing high oxygen concentration level (up to ~ 3 at.%) after being implanted at elevated temperature with 16O+ ions. For implants conducted at temperatures lower than 150°C, the α-Si layer expands via layer by layer amorphization at the front and back amorphous–crystalline (a–c) interfaces. When performed at temperatures above 150°C, 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°C revealed an array of microtwins and a dislocation network band in the recrystallized material. In samples implanted at 550°C, only a buried dislocation network band is observed.