Minority carrier lifetime in the region close to the interface between the anodic oxide and CdHgTe

Abstract

This paper describes minority carrier lifetime in n-type CdHgTe surface layers, especially the relationship between minority carrier lifetime and dislocations. A new method has been developed to evaluate lifetime in the surface layer of semiconductors. This method measures the concentration of minority carriers remaining after injection by utilizing surface potential measurement of an MIS diode. Computer simulation reveals how dislocations affect minority carrier lifetime and confirms the validity of this method. Experimental results indicate the dislocation-induced recombination is dominant for dislocation densities over 5×10 5 cm -2 and that minority carrier lifetime is inversely proportional to dislocation density. These results are similar to the results of the R 0 A product as a function of dislocation densities that have been reported by Colombo and Syllaios. The conjugate pairs r (radius of dislocation pipe) and s (recombination velocity at the dislocation site) are 0.3 to 0.5 cm 2 s -1. The lifetimes become almost constant - scatter 3 to 4 μs - for dislocation densities less than 2×10 5 cm -2. Lifetime is not dominated by dislocations in this dislocation density range.