Backside sputter depth profiling of phosphorus diffusion from a polysilicon source

A technique based on silicon-on-insulator (SOI) substrate was developed for backside sputter depth profiling of phosphorus diffusion from a polysilicon source. The backside silicon of SOI wafer was thinned by grinding to 30 μm using 0.5 μm diamond paper. Samples with different phosphorus concentrations in the polysilicon diffusion source and annealed at 900, 925, and 975°centigrade were selected for analysis. A simple grinding method with selective silicon wet etch resulted in high quality surfaces for backside sputtering.