Solid phase epitaxy of polycrystalline silicon films: Effects of ion implantation damage

Thin polycrystalline silicon films (2100 Å) were deposited on chemically cleaned silicon substrates by low-pressure chemical vapor deposition. The polysilicon films were then amorphized by 28Si ion implantation at reduced temperatures with damage densities ranging from 1.25×1024 to 1×1025 eV/cm3. Isochronal annealing of the films was performed at 550–1000 °C in a flowing N2 ambient. It was found that the minimum temperature at which the films recrystallized epitaxially is inversely proportional to the implantation damage density. For an amorphized film recrystallized at 550 °C on an antimony heavily doped silicon substrate, secondary ion mass spectroscopy data show that solid-state out-diffusion and autodoping effects are negligible.