Photoconductive Analysis of Ion Implantation Damage and Annealing in Silicon Wafers

This work describes the use of a new method of detecting residual damage centers, which are produced in ion-implanted silicon. Contactless resonant-coupled photoconductive decay (RCPCD) measures the minority-carrier lifetime in the unimplanted region of the wafer. The analysis and data show that the lifetime is dominated by recombination in the implanted volume. By varying the wavelength of the RCPCD excitation, one can determine that the dominant recombination occurs in the implanted region. The data show that the carrier lifetime increases by orders of magnitude as the recombination mechanism changes from defect to Auger recombination. The latter arises from high-density, electrically activated acceptors in p -type silicon after thermal annealing.