Crystal quality improvement of solid-phase crystallized evaporated silicon films by in-situ densification anneal

An in-situ densification anneal at 550 °C was applied to e-beam evaporated a-Si films on Si (1 0 0) wafers in a non-UHV environment. The c-Si films were then obtained by annealing the as-deposited a-Si films at 575 °C in a tube furnace. It is shown that the crystal quality of the c-Si films obtained from low-rate (50 nm/min) evaporated a-Si film is considerably improved by the densification anneal, whereas densification has no beneficial effect on c-Si films obtained from high-rate (300 nm/min) evaporated a-Si. However, the improvement of c-Si obtained from low-rate evaporated a-Si is not due to a significant difference in the oxygen content in the films. It is suggested that the improvement of the c-Si films is related to structural relaxation induced by the densification anneal of low-rate evaporated a-Si.