O2 and Ar plasma processing over SiO2/Si stack: Effects of processing gas on interface defect generation and recovery

Defect generation and recovery at the interface of a silicon dioxide/silicon (SiO2/Si) stack are studied in oxygen (O2) or argon (Ar) plasma processing and post-annealing. Defect generation is recognized to be dependent on the processing gas and the SiO2 layer thickness. O2 plasma processing shows a strong incident-ion energy dependence, where ion’s implantation, diffusion, and reactions in the SiO2 layer play important roles in defect generation. A similar dependence is observed for Ar plasma processing; however, it also shows the photon effects in defect generation for a thick SiO2 layer. Defect recovery is demonstrated by annealing, where recovery depends on the annealing temperature as well as the amount of defects generated at the interface.