Method and measuring instrument for identifying the diffusion length of the minority charge carriers for non-destructive detection of flaws and impurities in semiconductor crystal bodies

摘要

Method and measuring instrument for identifying the diffusion length of minority charge carriers for non-destructive detection of flaws and impurities in semiconductor crystal bodies. The method provides that the semiconductor crystal body is positioned between two electrolyte-filled measuring chamber halves and that the minority charge carriers of the photocurrent that results at a front side of the semiconductor crystal body due to irradiation is detected by an applied constant voltage between a backside of the semiconductor crystal body and a rear electrolyte at the backside of the semiconductor crystal body. Taking the thickness (D) of the semiconductor crystal body into consideration, the diffusion length (L) can be calculated from a mathematical equation using the quotient of the minority charge carrier current IGI/O occurring at the backside and at the front side of the semiconductor crystal body. The method provides topically resolved measurements for irradiation of the semiconductor crystal body. A measuring instrument for the implementation of the method is disclosed. The method can be used for determining the quality of semiconductor crystals.