Process for making BiCMOS integrated circuit having a shallow trench bipolar transistor with vertical base contacts

摘要

An improved bipolar transistor of a BiCMOS integrated circuit is fabricated by utilizing a shallow trench structure. The shallow trench defines an active base and a self-aligned emitter. The base resistance of the transistor is reduced because a vertical, rather than lateral, link base, which connects an extrinsic base to the active base, is formed. In addition, the overall area is reduced, which provides for a lower collector to base capacitance.