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.able to detect the dark current inhomogeneities in semiconductor devices such as solar cells, have been proposed. It is based on the principles of dynamical heating of defect dots by the pulse dark current and registration of the temperature alteration by the measurement of the external reflection from the semiconductor surface. Lock-in technique and statistical evaluation of the modulated reflectance data were used to improve the method sensitivity. A temperature waves process is proved to be a reason of reflectance modulation under impulse current applied to the tested solar cells. Spatial distributions for the DORT signal were obtained. q1999 Elsevier Science B.V. All rights reserved