The distribution of boron and arsenic in SOI wafers implementing SIMS

Abstract

Silicon-on-Insulator (SOI) material is becoming increasingly more important for low-power, low-voltage applications. In this study, boron (B) and arsenic (As) implanted SOI wafers have been investigated using Secondary Ion Mass Spectrometry (SIMS). It is shown that efficient charge compensation in the oxide layer is required to obtain dose information at the active layer/oxide interface. A variety of implant energies and annealing conditions have been studied. The results show that there is considerable "pile-up" of boron at the interface between the active layer and buried oxide due to preferential migration to interfacial defects following implantation and annealing processes. This "pile-up" is shown to be dependant on the process parameters. A similar phenomenon is not apparent in the arsenic implanted wafers studied.