Emitter Saturation Current Densities Determined by Self-consistent Calibration: Impact of Laterally Non-uniform Lifetime Distribution on Calibration Accuracy

The impact of laterally non-uniform carrier lifetime on the determination of the emitter saturation current(Joe) from photoconductance-based measurements, based on the self-consistent method proposed by Trupke and Bardos, is investigated using a model assuming two adjacent regions with considerably difference Joe. It is shown that the method can result in an underestimation of the mean Joe if the distribution of the Joe across the sensed area is not uniform. From simulation it is verified that t he error can be eliminated through independent measurement of the sample optical properties. The self-consistent calibration mechanism is also studied by the model. Experimental measurements confirm the model predictions.