Oxygen and related defects in Czochralski silicon crowns

Abstract

For the purpose of this thesis work, four n-type CZ silicon ingots with different crown tapered angle and shouldering area were characterized in order to understand the oxygen behavior and related defects on ingot top cuts and its influence on material lifetime. A p-type CZ silicon ingot was also characterized in order to have a reference material for comparison. Differences in lifetime between the crowns were observed and a strong correlation between the crown tapered angle and oxygen concentration and distribution was established. The crown with the higher tapered angle has the highest lifetime. In contrast, the crown with the lower crown tapered angle has the lowest lifetime. The crystal body quality can be influenced by the top ingot quality in what concerns the interstitial oxygen concentration and distribution. Thus, analyzing the early body of each ingot, it might be possible to predict the crystal body quality.