Spatial distribution of dopants and oxygen-related defects in antimony-doped Czochralski silicon

Abstract

Antimony (Sb)-doped Czochralski (Cz)-grown silicon (Si) wafers would feature superior performances in comparison with the conventional phosphorus (P)-doped wafers and start to be deployed into mass production. However, published studies about the properties of Sb-doped wafers for solar cells are rather scarce. This work investigates the spatial (i.e., axial and radial) distributions of Sb, interstitial oxygen (O_i) and oxygen thermal donors (TD), in Sb-doped Cz ingots processed with melt recharging (RCz), focusing on wafers representative of the whole RCz cycle. This study confirmed first the interest in Sb-doping for obtaining Si ingots and wafers with a controlled and narrowed resistivity range. Furthermore, the studied wafers featured low as-grown TD concentrations, low enough not to affect the bulk carrier lifetime (τ_b). Results also showed that Sb-doping does not significantly influence the TD formation kinetics. Last, the studied wafers featured relatively low O_i concentrations ([O_i]) below 7 × 10¹⁷ cm⁻³ for most samples, with rather flat [O_i] radial profiles. As these Sb-doped samples also presented low Thermal History Index values, they should not be prone to O-related defects-induced τ_b degradations during high temperature steps.