Sharp boron spikes in silicon grown at reduced and atmospheric pressure by fast-gas-switching CVD

Boron doping spikes in Si were grown by fast-gas-switching CVD at 800 and 850°C using Si2H6 and B2H6 in 0.03, 0.1 and 1 atm H2 as the carrier gas. The B2H6 doping gas was added for 2 s by two methods, namely during growth or as a flush while the Si2H6 flow was interrupted. High-resolution SIMS measurements have revealed extremely sharp and highly concentrated dopant profiles. Peak B concentrations up to 5×1021 cm-3 and, at 1 atm H2, a FWHM of 3 nm were obtained. Electrical measurements show that for B-spikes having a FWHM value of 4–5 nm, a sheet resistivity of as low as 580 O/ \Box can be obtained