Measuring process and appliance for the diffusion length determination of minority charge carriers for the interference-free detection of defects and pollutants in semiconductor crystal bodies

摘要

The method provides for the semiconductor crystal body (3) to be placed between two electrolyte-filled measuring half-chambers (1 and 2) and the minority charge carrier of the photocurrent produced by irradiation on the front side of the semiconductor crystal body (3) with the aid of an applied direct voltage between the rear side of the semiconductor crystal body (3). and to detect back electrolyte (12) and on the back of the semiconductor crystal body (3). From the quotient of the minority charge carrier current IG / IO occurring on the back and on the front of the semiconductor crystal body (3), the diffusion length (L) can be determined using a mathematical equation, taking into account the thickness (D) of the semiconductor crystal body (3). The method provides spatially resolved measurements when the semiconductor crystal body (3) is irradiated at points. A measuring device for carrying out the method is specified. The method can be used to determine the quality of semiconductor crystals.