MEASUREMENT CONSIDERATIONS FOR ZERO-FIELD TIME-OF-FLIGHT STUDIES OF MINORITY-CARRIER DIFFUSION IN III-V SEMICONDUCTORS

The zero-field time-of-flight technique for measuring minority carrier diffusivity in III-V semiconductors is critically examined. The effects of photon recycling, circuit parasitics and test structure design are examined in detail as is the analysis procedure used to extract the minority carrier diffusion coefficient. The analysis shows that substantial errors can result if test structures are not carefully designed. Guidelines for designing test structures and for analyzing measured results are presented. This work demonstrates that the technique can be an accurate and convenient method for characterizing the doping-and temperature-dependence of minority carrier diffusivity, or equivalently mobility, in compound semiconductors.