The common emitter current gain (/spl beta//sub 0/) of the bipolar transistor in the IGBT (insulated gate bipolar transistor) structure semiconductor device is measured in this paper. The first step of the measurement is to find the early voltage (V/sub A/) of the device. Then the early voltage is used for calculating the base width (W/sub B/) and the doping density in the base (N/sub B/) of the device. Finally, we can use those parameters to calculate the common emitter current gain. The junction capacitance of the collector and the emitter are also measured to find the doping concentration in the emitter. All of the parameters are used for calculating the middle frequency common emitter current gain (/spl beta//sub 0/). The experimental results show that measurement errors are not more than 5%.