Lateral scanning of Si based systems by measurements of the microwave photoconductance

Photoconductance measurements in the microwave frequency range for the characterization of semiconductors are discussed. The merits of different ways of excitation, i.e. pulsed, harmonically modulated and stationary are considered in view of the information given and the spatial resolution. The relation between the diameter of the excitation pulse and the spatial resolution is investigated. Measurements of silicon wafer covered by silicon nitride films are presented as examples.