The investigation of defects in silicon by modulated optical reflectance measurements has proven to be a powerful and easy-to-use method of nondestructive materials characterization. This technique has been used to monitor ion implant dose [1] and measure polishing damage [2] in silicon wafers, and to map O2 swirl precipitates in Czochralski-grown silicon [3]. Laser-induced modulated reflectance offers advantages over some related thermal-wave techniques: it is contactless, and because it can be performed at modulation frequencies of several MHz, it offers micron-scale resolution. Its noncontact and nondestructive nature makes this technique attractive for production-line use in the semiconductor industry.