窒素ドープＣｚｏｃｈｒａｌｓｋｉシリコン結晶の赤外吸収測定

Abstract

Nitrogen doping is promising to reduce grown-in defects in Czochralski silicon (CZ-Si) crystal. It is necessary to measure the nitrogen concentration accurately. As the nitrogen concentration is very low, nitrogen absorption is affected by various absorptions such as those by lattice vibration and oxygen. Procedures to cancel them were developed. As the result, the detection of weak nitrogen-related peaks became possible. As nitrogen in CZ-Si crystal forms complexes with oxygen, we assigned the peaks and proposed to measure the N-N related peak at 963 cm-1 as well as those at 996 and 1018 cm-1 caused by N-O complexes. Conversion coefficient from the sum of absorption coefficients of these peaks to the nitrogen concentration estimated by segregation coefficient was confirmed to be nearly equal to the value reported for floating zone silicon (FZ-Si) crystal.