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The parameters of crystalline semiconductor such as types of semiconductor,uniformity of impurity concentration of doped wafer, majority charge carrierconcentration, sheet resistivity of doped wafer surface play an important rolein solar cell fabrication process during emitter diffusion, that is the mostcritical step. In this paper, we have used a low cost in house made hot probe measurement setup. A hot plate was used to heat up the wafer up to 100°C.Two k-type thermocouples were placed simultaneously in contact with thehot and cold surface of the wafer to measure the temperature in situ for bothhot and cold probe. We have used two copper probes with a voltmeterconnected to measure the potential difference (thermoelectric voltage)between two probes for various temperatures up to 100°C with an interval of10°C. We have taken measurement for commercial silicon wafer (thickness200 µm) and one side polished 4 inch diameter Si wafer (thickness 660 µm) todetermine the wafer type (n-type or p-type). We also calculated thermopower or Seebeck coefficient from the voltage vs. time curve, that is constantfor particular substrate. As a process monitoring tool for solar cell fabricationprocess, after n-type diffusion using POCl3 on p-type silicon wafer ofthickness 200 µm, we have done wafer mapping that gives us theinformation of doping uniformity over the whole surface of wafer both front and back side.