The formation of shallow donors was studied in n-type samples which had been implanted with 100keV H ions to a dose of 1015/cm2 and annealed (100 to 800C, 0.5h). The H profiles were measured by using secondary-ion mass spectroscopy. The zero-bias depletion-layer width which was measured at 90K was below the pre-implantation value after annealing at 300 to 500C; thus indicating the introduction of shallow donors. Two types of shallow donor (HS1, HS2) were shown to form, within this temperature range, by means of carrier profile measurements. The HS1 donor was observed at annealing temperatures around 300C, and exhibited a concentration peak at a depth near to the mean projected range of implanted H. The HS2 donor was observed after annealing at 350 to 450C, and spread towards the surface with almost flat profiles. A comparison of carrier and H profiles indicated that the HS1 donor was H-related. It was possible that the HS2 donor was also H-related.

Y.Tokuda, A.Ito, H.Ohshima: Semiconductor Science and Technology, 1998, 13[2], 194-9