Damage Formed by Plasma Boron Doping in Silicon

Abstract

Damage formed by DC plasma doping of boron to silicon is studied. Damage density is measured by 1.5 MeV He+ Rutherford backscattering spectrometry and photoacoustic displacement techniques. These damage density measurements show that lower-damage doping can be achieved in plasma doping compared with that of ion implantation. Impurity diffusion does not occur as rapidly in this doping as seen in B+ and BF2+ implantations. The diffusion coefficient of boron is as low as 4.9× 10-15 cm2/s at 950° C in this doping. This coefficient is 5 and 40 times lower than that of B+ and BF2+ implantations, respectively. Correlation of the diffusion coefficient with damage density is found. A shallow and high peak carrier concentration p+ layer can be formed by plasma boron doping.