Application of Dynamical Optical Reflection Thermography (DORT) for detecting of dark current inhomogeneity in semiconductor devices

A novel technique named Dynamical Optical Reflection Thermography (DORT) ab le to detect the dark current inhomogeneities in semiconductor devices such as solar cells, have been proposed. It is based on the principles of dynam ical heating of defect dots by the pulse dark current and registration of t he temperature alteration by the measurement of the external reflection fro m the semiconductor surface. Lock-in technique and statistical evaluation o f the modulated reflectance data were used to improve the method sensitivit y. A temperature waves process is proved to be a reason of reflectance modu lation under impulse current applied to the tested solar cells. Spatial dis tributions for the DORT signal were obtained. (C) 1999 Elsevier Science B.V . All rights reserved.