Semiconductor device and drive circuit using the semiconductor devices

摘要

A high-speed bipolar transistor is provided which is improved in the effect of heat radiation without increasing the substrate capacitance. The heat radiation connection between a base region and a silicon substrate includes a p+ extrinsic base polysilicon electrode and a polysilicon layer buried in an isolation groove with a very thin silicon dioxide side wall. Accordingly, the heat generated at the base is radiated through this path to the silicon substrate. Further, the film thickness of the silicon dioxide on the inner wall of the isolation groove is sufficiently increased compared with previous structures to prevent an increase in the substrate capacitance. Consequently, there can be obtained a bipolar transistor which operates at high speed, and is improved in the effect of heat radiation without increasing the substrate capacitance.