Germanium Doping and Impurities Analysis on Industrial Scale Mc-Silicon Ingot

Abstract

With mc-silicon (multi-crystalline silicon) being the most favorable feedstock for solar cell, germanium was reported to be a promising dopant to improve the quality of silicon crystal growth. In this paper, we investigated the feasibility of germanium doping for industrial scale production. A homogeneously distribution of germanium across usable section is presented, and subsequently we optimized our recipe for better controlling it. Sopori etched pits were utilized to reveal dislocations in silicon wafers, and we found a reduced dislocations density in germanium doped samples. Carbon and oxygen are two inevitable significant impurities during silicon ingot casting. In this paper, experimental results showed the impact of carbon on minority charge carrier lifetime and on interstitial oxygen. In addition, Isostatic pressing method is proved to be very prospective for recycling quartz crucibles.