ON THE DATA-ANALYSIS OF LIGHT-BIASED PHOTOCONDUCTANCE DECAY MEASUREMENTS

The use of bias light is common practice today in photoconductance dec ay (PCD) measurements to analyze semiconductor samples with injection- level dependent recombination parameters (i.e., surface recombination velocity and/or bulk lifetime). Recently, it has been shown on theoret ical grounds that the previously reported recombination parameters fro m light-biased PCD experiments are not the actual properties of the in vestigated sample, but so-called differential recombination parameters [R. Brendel, Appl. Phys. A 60, 523 (1995)]. In the present article th e theory relevant to light-biased PCD measurements is discussed in det ail and subsequently applied to monocrystalline silicon wafers with ni tride and oxide passivated surfaces in order to verify the deviations between the differential and actual surface recombination velocities. Special emphasis is paid to the experimental fact that the injection l evel cannot be reduced below a minimum value due to signal-to-noise pr oblems. (C) 1996 American Institute of Physics.