Room-temperature plasma doping without bias power for introduction of Fe, Au, Al, Ga, Sn and In into Si

It is demonstrated by use of secondary ion mass spectroscopy that some impurities, including Fe, Au, Al, Ga, Sn and In, can be doped into Si wafers with depths of tens nanometer but quite high densities in radio frequency (RF)-excited plasma without any bias power at room temperature. This process is referred to as plasma doping without bias (PDWOB). In PDWOB, the quantity and depth of an impurity doped into the Si wafer depend on the character of the impurity, power of the RF that excites the plasma and the processing time of the PDWOB. The good fitting of the complementary error function distribution with the experimental data of the concentration distributions of the impurities doped into Si wafers indicates that PDWOB is a result of room-temperature diffusion of impurities in Si stimulated by vacancies and Si self-interstitials induced by plasma. The application prospects of the PDWOB, including doping ultra-thin films, ultra-shallow junctions and two-dimensional materials, are emphasized.