Optical beam induced current measurements: principles and applications to SiC device characterization

This paper deals with the characterization of SiC devices by optical beam induced currents (OBIC). OBIC is a technique that measures a photocurrent in response to a fine UV laser beam that is scanned laterally over the surface of the device. In this way a number of important material and device parameters can be derived. We concentrate here on three aspects, the field profile in reverse biased diodes with particular emphasis on field terminating issues at the device edges under high reverse voltages; the minority carrier lifetimes in 6H‐SiC; and the determination of ionization coefficients for electrons and holes in 6H‐SiC. The latter are important material parameters for the modelling of high power devices and determine their break‐through voltage. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)