Surface and interface roughness after thermal oxidation of As, B, and Si implanted silicon wafers

The surface roughness after thermal oxidation of Si implanted with As, B and Si was investigated by AFM. For wet processes at 920 ¬?C the As implanted samples are characterized by a marked roughness. RBS measurements indicate that As atoms segregate at the Si/SiO2 interface. B and Si implanted samples show instead a roughness very similar to that of virgin Si. The surfaces after dry oxidation at 1100 °C are all quite smooth with the only exception of the Si implant. We explain this phenomenon with the formation of oxidation induced stacking faults. The low roughness of the As implanted samples has been explained in terms of the prevalence of As diffusion with respect to the interfacial segregation.