Photorefractive Imaging of Semiconductor Wafers.
01 January 1988
Making use of the photorefractive effect, we have developed a versatile method of imaging various crystal properties of semi- insulating compound semiconductors. The magnitude and time evolution of refractive index gratings are monitored via diffraction. The observed diffraction is directly related to the electric fields present and quantitative information concerning the spatial variation of dark conductivity, photoconductivity and deep level absorption can be extracted. Wafers of undoped GaAs and InP:Fe have been characterized in this manner and comparisons of images are made which demonstrate the capabilities of this technique.