COMPARISON OF 11 B + AND 49 BF 2 + AT LOW IMPLANTATION ENERGY IN GERMANIUM PREAMORPHIZED SILICON

The purpose of this work is to compare 11 B + and 49 BF 2 + implantations for the formation of shallow ( + /n junctions. In one hand, 49 BF 2 + implants can lead to higher sheet resistance than 11 B + implants due to the presence of fluorine. In the other hand, boron enhanced diffusion is less important in presence of fluorine which would lead to shallower junctions. For this comparison, 11 B + and 49 BF 2 + implants were done into crystalline and preamorphized silicon wafers and the results were analyzed by SIMS, Spreading Resistance and TEM. The implants of 11 B + and 49 BF 2 + into Ge preamorphized Si followed by RTA allow to form junctions <0.1 μm, without any defect visible by TEM.