Isothermal Annealing of Ion Implanted Silicon With a Graphite Radiation Source

ABSTRACTBoth (100) and (111) Si wafers were implanted with As, P or B to doses from 1013 to 1016/cm2 and annealed with a Varian IA-200 isothermal annealer. The anneal occurs in a vacuum using infrared radiation for exposure times of 5 to 30 sec. Sheet resistance (Rs), Hall effect, RBS and SIMS were used to analyze the wafers. For each dopant a decreasing Rs occurs with increasing exposure time until a minimum value is reached. Longer anneals produce increased dopant diffusion, and the Rs for As and P implanted wafers increased unless the wafer was capped with 0.05 μm of SiO2 which prevents a loss of dopant. The results for (100) wafers are better than for (111) with As doses ≤1015/cm2, however at doses >1015/cm2 the (100) and (111) results are comparable. The As implanted, isothermally annealed layers were thermally stable for As concentrations ≤2E 20/cm3.