Boron-δ doped Si grown by ultra-high vacuum chemical vapor deposition

We report on the properties of p-type boron-δ doped layers in Si prepared by novel ultra-high vacuum chemical vapor deposition (UHVCVD) using the growth interruption. This UHVCVD system, with a water-cooled stainless steel growth chamber, allows a higher growth rate and also maintains a high-quality film quality. To suppress the bordering of δ-doping distribution during the growth, the growth is proceeding at a low temperature (550 °C). Secondary-ion mass spectrometry (SIMS) analysis reveals that peak B concentration is linear in the doping time at a fixed B2H6 flow rate. Furthermore, sharp B depth profile of higher concentration was obtained after increasing of B2H6 flow rate and pumping time between steps. The peak concentration of doping spikes reaches to 1×1019 cm−3 and the full-width at half-maximum (FWHM) lowers to 67 Å with the up slope as steep as 5 nm per decade.