Spatially resolved non-contact bulk and surface photovoltage response in semiconductors

The principles of non-contact ac photo-voltage measurements and the use of the photovoltaic effect in nondestructive evaluation are assessed. Applications in the nondestructive inspection of VLSI wafers during processing and for early electrical testing prior to chip packaging are evaluated. Scanning ac surface and bulk photo-voltage methods are described using solid state and optical premises. Areas where the measuring methods can be used at low photo-excitation levels to probe fundamental processes such as trapping energy and carrier lifetime and kinetics are discussed.