Semiconductor bipolar transistors with base and emitter structures in a trench and process to produce same.

摘要

The disclosure relates to an integrated circuit substrate having a bipolar transistor wherein the base (25) and emitter (27) regions are disposed in a first trench in the substrate (5) and the collector (29) is disposed in the substrate spaced from the trench. The collector is preferably a second trench. The trenches are filled with doped polysilicon (31,33) wherein the dopant has diffused in part into the side walls of the trenches. The method of forming the integrated circuit comprises the steps of providing a semiconductor substrate (5) of predetermined conductivity type (N), forming a shallow region (15) of opposite type (P) conductivity in the substrate, forming a trench in the substrate extending through the shallow region, forming base (25) and emitter (27) regions in the trench and forming a collector region (29) in the substrate (5) spaced from the trench.