Investigation of Ar ion implant gettering of gold in silicon by m.o.s. and Rutherford backscattering techniques

The gettering of Au in silicon has been investigated using m.o.s. techniques and Rutherford backscattering. Silicon wafers were intentionally contaminated with Au, and then Ar ion implant was performed on the back surface of the wafer and the damaged layer annealed at 1050°C for times of 15 and 60 minutes. Comparison of generation lifetime between gold wafers and gold implant-gettered wafers, obtained from the response of m.o.s. capacitors to a linearly varying voltage showed a marked improvement for the implant gettered wafers. Rutherford backscattering using 14N+ ions was carried out on the wafers, both on the implant damaged layer and on some 30¿40¿m in the bulk of the material. The Au concentration in the implant damaged layer was higher than in the bulk of the same wafer for both anneal times, indicating that Au had been effectively gettered. The backscattering speetra also showed other impurities such as Br, Cu, Fe, Sb, Sn and Te present in higher concentration in the implant damaged layer than in the bulk