The implementation of a reduced-field profile design for high-performance bipolar transistors

The first realization of a reduced-field design concept for advanced bipolar devices using the low-temperature epitaxial (LTE) technique to form the base layer is described. By inserting a lightly doped collector (LDC) spacer layer between the heavily doped base and collector regions, it is successfully demonstrated that the collector-base (CB) junction avalanche multiplication can be reduced substantially while maintaining high collector doping for current density consideration. Similar applications of the LDS technique to the emitter-base (EB) junction also results in a lower electric field, thus less EB junction reverse leakage. The feasibility of the reduced-field profile design concept is demonstrated using a LTE-base device structure.<>