Simplified surface photoreflectance measurement system

We present a simple and economical photoreflectance measurement methodology that can easily be adapted to conventional scanning optical microscopes. In this design, the laser source is sine-wave modulated so that the second-harmonic modulation distortion within the optical probe beam before and after reflection off the sample surface can be monitored. The desired photoreflectance measurement, which is taken as the change of reflectance as a result of varying the incident optical power, is then obtained from the change in the ratio of the fundamental and second-harmonic signals. We demonstrate our set-up and technique by measuring the implantation damage in nitrogen-implanted silicon samples.