Simulation of Collector Current Distribution in Heterojunction Bipolar Transistors Using Newly Proposed Empirical Expression

This paper proposes a new empirical expression of the collector current in multifinger HBTs (Heterojunction Bipolar Transistors) as a function of the junction temperature, which is essential for optimizing the device layout and the ballasting resistor. The novel calculation yields more precise agreement with measured data than the conventional one. This scheme should be useful for elucidating the actual collector current distribution over each finger in multifinger HBTs.