Grain growth during transient annealing of As-implanted polycrystalline silicon films

Polycrystalline silicon films deposited on oxidized wafer surfaces were implanted with As and annealed on a Varian IA-200 rapid thermal annealer. The effects of annealing conditions on resultant grain size of original as-deposited columnar grains are presented with a modified model for interfacially driven grain growth. During an initial temperature rise to 910°C the original grain size (39 nm) and dopant profile are not significantly altered. At 1145°C the grains have grown to 90 nm and the As is uniformly distributed throughout the film. Additional annealing to 1300°C in 20 s causes grains to grow to 260 nm. Further grain growth is retarded due to the 300-nm film thickness. During annealing of unencapsulated films a substantial loss of As results in a lower rate of grain growth. When grain size increases, Hall mobility increases and resistivity decreases.