Process for determining the recombination velocity of minority charges at the borders between semiconductors and other substances

摘要

For the two-stage measuring process, one half cell (1, 2) with an electrode (7, 8) is in each case attached to the front (9) and rear (10) of the semiconductor wafer (3), only the half cell (2) at the rear (10) being filled with an electrolyte (6) in the first measuring step. The minority-carrier photocurrent I2' flowing between electrode (8) and semiconductor surface (10) during irradiation of the front (9) of the semiconductor crystal (3) of the rear half cell (2) is dependent on the speed of recombination S at the front (9). In the second measuring step, the front half cell (1) is also filled with electrolyte (5), and both the rear photocurrent I2 with the now negligible influence of S, and the front photocurrent I1 are measured. From the photocurrents measured, the speed of recombination can be calculated with the aid of a mathematical formula. The local distribution of the speed of recombination is obtained with point-shaped irradiation and screening over the crystal wafer (3). …IMAGE…