Direct measurement and analysis of highly injected intrinsic base potential

Highly injected intrinsic base potential was directly measured by using a novel test structure. Measured distribution of the intrinsic base gives useful information for investigation of the high-injection operation of a bipolar transistor. Using this method the effect of base dose (current gain) on emitter crowding was investigated. In general, a knee current, which is defined as the collector current when h _FE becomes one-half of its maximum value h_FE0 , increases as the base dose increases. However, it was observed that the knee current saturated when the base dose was high. From the measurement results, it was clarified that this phenomenon is due to the emitter crowding effect