Photoluminescence mapping system applicable to 300 mm silicon-on-insulator wafers

A unique system has been developed for photoluminescence (PL) mapping on silicon-on-insulator (SOI) wafers. We used an ultraviolet laser as an excitation source to excite an ultrathin top Si layer of an SOI wafer. The beam size was varied from 1 to 1000 mum, depending on the required spatial resolution. We were able to perform not only macroscopic mapping on a full wafer of 300 mm diameter but also microscopic mapping on a particular area of interest. Monochromatic detection of PL light allowed us to obtain mappings of deep-level emission as well as band-edge emission. We revealed a characteristic nonuniformity in full wafer mapping and a micron-sized irregularity in the top Si layer of a commercial SOI wafer.