On the assumed impact of germanium doping on void formation in Czochralski-grown silicon

Abstract

The assumed impact of Ge doping on void formation during Czochralski-growth of silicon single crystals, is studied using scanning infrared microscopy. It has been reported that Ge doping leads to a reduction in the flow pattern defect density and of the crystal originated particle size, both suggesting an effect of Ge on vacancy concentration and void formation during crystal growth. The present study however reveals only a marginal-if any-effect of Ge doping on grown-in single void size and density. Double and multiple void formation might however be suppressed partially by Ge doping leading to the observed decrease in flow pattern defect density. The limited effect of Ge doping on single void formation is in agreement with earlier findings that Ge atoms are only a weak trap for vacancies at higher temperatures and therefor should have a smaller impact on the vacancy thermal equilibrium concentration and on single void nucleation than, e.g., interstitial oxygen and nitrogen.