New microwave techniques in surface recombination and lifetime studies

A new method of measurement of recombination effects in semiconductors is described. Germanium and silicon slabs are prepared to fill the cross section of a waveguide and changes in microwave transmission as a function of conductivity of the semiconductor provide a direct measurement of lifetime. It is shown that under specific conditions of thickness of the sample a linear relationship exists between the transmitted power and the conductivity, even when the conductivity approaches the value of the product of angular frequency and permittivity. Furthermore, the new technique of lifetime measurement is simpler than previously described microwave and conventional dc methods and can be used to cover a broader range of conductivities. Experimental data are given to illustrate the principles.