Characterization of bulk microdefects in Ge single crystals

Abstract

The work reported here concerns the characterization of bulk microdefects in germanium single-crystal wafers. From comparison with the case of silicon, it is expected that bulk microdefects are formed due to diffusion and interaction of self-interstitials and vacancies during Czochralski growth, solely dependent on the growth parameters. Unfortunately, several of the defect characterization methods, which can be used for silicon, fail in the case of germanium due to its lower band gap. Therefore, the possibilities of two alternative techniques, x-ray topography and small-angle x-ray scattering, respectively, were investigated. The results, combined with a characterization of the material surface using scanning laser reflectometry, indicate that in Ge, the same kind of intrinsic growth-related defects exist, as in Si.