Influence of rapid thermal processing on carrier concentration in high resistivity silicon

In this study, we report changes in the carrier concentration of high resistivity Si wafers after rapid thermal annealing (RTA) anneals measured by spreading resistance technique. Spreading resistance technique (SRP) profiles clearly show the generation of donor centers with concentrations and depth distributions comparable to those of vacancy-related centers reported in the literature. Changes of carrier concentrations as a function of RTA temperature, duration, ramp down rate, and subsequent annealing in the 800-1000 degrees C range are consistent with the earlier literature data. The influence of annealing ambient is also studied. Annealing in pure Ar atmosphere leads to profiles dominated by in-diffusion of vacancies generated at the surface, while annealing in oxidized ambient results in well-known profiles controlled by out-diffusion of vacancies generated in the wafer bulk. Studies of the wafers with different oxygen content show that the concentration of the generated donors is directly proportional to O-i concentration. (C) 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim