Boron diffusion in silicon from a boron nitride source (PDS BN-975) with hydrogen injection has been studied experimentally.
The predeposition temperature is 930℃ the percentage of $H_2$ is varied from 0% to 4%, and soak times of the samples are 15 min., 30 min., 50 min.. The minimum wafer-to-wafer sheet resistance variations are ±2% when 2% hydrogen is added.
Oxidation induced stacking faults are inspected with Wright Etch. In hydrogen injection process, the OSF shrinkage is enhanced by about 15% when compaired with non-hydrogen process. The reduction of masking oxide thickness at 930℃, 50 min. soak time is about 1600Å with 2% - $H_2$ process. In non-hydrogen process, only about 1000Å of masking oxide is consumed. Finally, MOS capacitors with diffused channel stop have been fabricated and storage time is measured. From this experiment, it has been shown that the hydrogen injection process gives longer storage time than non-hydrogen process for the diffusion of channel stop region.
