Time resolved microwave conductivity measurements for the characterization of transport properties in thin film micro-crystalline silicon

Abstract

The time resolved microwave conductivity (TRMC) technique measures the transient change in microwave reflectivity that carriers generated by a laser pulse induce in a sample. The reflectivity variation with time reflects, combined with the mobility, the carrier generation or recombination, either in the bulk or at the interfaces. From the measurements, one may deduce the carrier lifetime, and the carrier mobility, either in the bulk or near the interface. Computer simulations, for thin films deposited on glass, has been performed so as to modelize the TRMC transients. The transport properties of various micro-crystalline silicon thin films, deposited either with laser annealing technique, or with layer by layer technique, are obtained from TRMC. The results are compared with other characterizations. The TRMC mobility is smaller than field effect mobility in micro-crystalline silicon. The TRMC diagnostic can be used for material optimization.