CHARACTERIZATION OF SILICON-WAFERS BY TRANSIENT MICROWAVE PHOTOCONDUCTIVITY MEASUREMENTS

The possibilities and limitations of characterizing single crystalline silicon wafers with a contactless, nondestructive transient photoconductivity method, i.e. the time resolved microwave (TRMC) method has been demonstrated. The bulk lifetime and the diffusion constant of minority charge carriers in n - and p -doped silicon wafers (rho: 1-200-OMEGA cm) were determined in two different ways: by varying the wafer thickness and by changing the surface recombination velocity via different etching treatments. Using electron irradiated (14 MeV) wafers, it was shown that this method can be used for the detection of changes in the bulk lifetime.