BREWSTER-ANGLE SPECTROSCOPY - A NEW METHOD FOR CHARACTERIZATION OF DEFECT LEVELS IN SEMICONDUCTORS

A new optical method which allows the identification of electronic defects in semiconductors is presented. Deep level characterization is done by detecting changes of the Brewster angle induced by optically excited transitions involving defects. An empirical model is developed which correlates the minima of the derivative of the Brewster angle as a function of photon energy with the energetic locations of defects in the semiconductor gap. Contactless room-temperature measurements on n-GaAs (100) and p-InP (111) clearly reveal defects with high accuracy, including the well known EL2 and EL12 centers in GaAs. The applicability of the method for semiconductor device technology processes is discussed.