Microreflectance difference spectrometer based on a charge coupled device camera: surface distribution of polishing-related linear defect density in GaAs (001).

ABSTRACT

We describe a microreflectance difference (microRD) spectrometer based on a charge coupled device (CCD), in contrast to most common RD spectrometers that are based on a photomultiplier or a photodiode as a light detector. The advantage of our instrument over others is the possibility to isolate the RD spectrum of specific areas of the sample; thus topographic maps of the surface can be obtained. In our setup we have a maximum spatial resolution of approximately 2.50 microm x 2.50 microm and a spectral range from 1.2 to 5.5 eV. To illustrate the performance of the spectrometer, we have measured strains in mechanically polished GaAs (001) single crystals.