Contribution of Thermal SiO2 Layers on Si Wafer Back Surfaces to Photoconductive Decay Time Measured with Microwave Reflection from Front Surfaces

Abstract

Two p-type silicon wafers, 420 µm in thickness, have been provided with different surface recombination characteristics. It is found that the back surface oxide layer greatly contributes to the photoconductive decay time in the wafer whose surface recombination rate is not large. However, the decay time is independent of the back surface oxide layer when the time is short because of the surface recombination.