We characterized a 4H-SiC wafer in various device processing steps for Schottky barrier diode (SBD) formation by photoluminescence (PL) spectroscopy and mapping. A PL mapping system was developed to perform high-speed full-wafer mapping as well as microscopic mapping of a region of particular interest with a spatial resolution down to 2 mum. Characteristic PL patterns corresponding to the ion-implanted regions such as channel cuts and field limiting rings of the SBD were successfully observed together with the patterns relating to defects present in the as-received state. We discussed a variation of intensity contrast of the respective PL patterns in the implanted wafer before and after activation annealing in the device process. Raman microprobe imaging was also performed complementarily on a defective area to examine the crystalline structure.