Method for the Microwave Measurement of Carrier Lifetime in Lightly Doped Silicon Ingots

Abstract

A further investigation is conducted into a new microwave method for evaluating bulk lifetime in silicon ingots [1]. It is shown that for lightly doped ingots transmission and reflection microwave measurements yield different values of the decay time of photogenerated excess-carrier density. The discrepancy is attributed to the influence of surface recombination. Measurements are compared with theoretical predictions for a semiinfinite semiconductor specimen. Data are presented on bulk lifetimes in ten high-quality silicon ingots grown by the float-zone process and doped with phosphorus by neutron transmutation doping. The lifetimes are measured by microwave transmission or reflection and by probe injection.