ANALYSIS OF MICROWAVE-SCATTERING FROM SEMICONDUCTOR WAFERS

The reflection and transmission coefficients have been calculated for one-dimensional wave propagation for various configurations in order to use the result for the contactless microwave lifetime measurement technique. Analytical approximations for low and high frequencies have been obtained and it has been shown that the reflection coefficient for nonhomogeneous conductivity can be approximated for relatively high frequencies by using the expression for the homogeneous sample and taking the average conductivity. The sensitivity of the microwave lifetime measurement has been calculated and it has been shown that for some combinations of the conductivity and sample thickness, a frequency exists at which the sensitivity equals zero. The case in which one side of the sample has been coated by a high conductivity material has also been studied and it has been shown that the resulting sensitivity changes significantly.