RAPID THERMAL ANNEALING OF HIGH-CONCENTRATION MIXED AS/IN-IMPLANTED AND P/IN-IMPLANTED SILICON SINGLE-CRYSTALS

The effect of group-V donor impurities on the behavior of indium atoms implanted into silicon single crystals has been studied by Rutherford backscattering spectrometry/channeling spectrometry, and differential Hall-effect/resistivity measurements. Flat arsenic or phosphorus profiles of concentrations between ∼1.4×1020 cm-3 and 3×1020 cm-3 were produced by As+ or P+ implantation followed by rapid thermal annealing (RTA) (20 s, 1100 °C). Subsequently In was implanted to peak concentrations of 1.7×1020 cm-3 or 3.5×1020 cm -3 and annealed by RTA (15 s, 700-1050 °C).Compared to single indium implants, the presence of the preimplanted group-V impurities is found to reduce the redistribution of the implanted indium atoms during RTA and to increase the concentration of indium atoms incorporated on (or close to) lattice sites (up to ∼2×1020 cm-3). The value of the indium substitutional fraction is found to be dependent on anneal temperature and type of donor impurity. A reduction in the free-electron concentration is observed in both the phosphorus and arsenic predoped samples at the same depths as that of the indium atoms.