Doping Si, Mg and Ca into GaN based on plasma stimulated room-temperature diffusion

It is demonstrated by use of the secondary ion mass spectroscopy (SIMS) some impurities, including Si, Mg and Ca, can be doped into GaN films with depths of ten nanometer and quite high surface densities in plasma without any external bias at room-temperature (RT). The physical mechanism of plasma doping without any external bias (PDWOEB) is RT diffusion stimulated by the plasma, which is very different from that of the plasma doping method with an external bias, which was called plasma immersion ion implantation in literature, whose physical mechanism is low energy ion implantation. Stimulated by a plasma with power of 750 W in 2 min, the RT diffusion coefficients of Si, Mg and Ca in GaN obtained by fitting the complementary error function distribution with their SIMS concentration distributions are 1.3E−15, 1.9E−16 and 1.2E−16 cm/s, respectively. The RT diffusion coefficients of Si and Mg have been enhanced 18 and 22 orders of magnitude, respectively, compared with the RT extrapolation values of the high temperature diffusion coefficients reported in literature.