TEM and SIMS study of the behaviour of fluorine in as-deposited amorphous and polysilicon annealed at 600 to 950C

Abstract

The behaviour of fluorine in as-deposited polysilicon (p-Si) and as-deposited amorphous Si (a-Si) layers after annealing in the range 600-950C us investigated. The p-Si and a-Si were deposited by LPCVD at 610 and 560C, respectively, implanted with F (5E15cm-2, 30keV) and annealed. The microstructure and fluorine distributions were investigated by TEM and SIMS. The results show that at >=650C F segregates to form inclusions of similar size and shape in both as-deposited a-Si and p-Si, the amount of F in the layer decreases and at the interface increases with increasing temperature. For the same anneal, more F reaches the interface in p-Si than in a-Si. Mechanisms explaining the microstructure and F distributions are discussed