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

The behaviour of fluorine (F) in as-deposited poly-Si (p-Si) and as-deposited amorphous-Si (α-Si) layers after annealing in the range 600-950°C is investigated. The p-Si and α-Si were deposited by LPCVD at 610°C and 560°C respectively, implanted with F (5xlO^l5/cm², 30keV) and annealed. The microstructure and F distributions were investigated by TEM and SIMS. The results show that at ≥650°C F segregates to form inclusions of similar size and shape in both as-deposited α-Si and p-Si. The amount of F in the layer decreases, and at the interface increases, with increasing temperature. For the same temperature, more F reaches the interface in p-Si than in α-Sί. Mechanisms explaining the microstructure and F distributions are discussed.