Method of forming a bipolar transistor portion comprising a self-aligned trench-isolated emitter.

摘要

A bipolar transistor (200) exhibits improved function due to its emitter structure. A single layer of conductive material (240) forms both the emitter contact (210) and the base contact (236) in the transistor (200) structure, which structure has particularly shallow emitter and base junctions (about 0.15 micrometer or less). The self-aligned emitter contact (210), isolated from the base contact (236) by a dielectric-filled trench (234), permits overall size reduction of the device, whereby junction area and accompanying leakage across junctions is reduced. In addition, when the structure of the bipolar transistor (200) is such that the dielectric-filled trench (234) isolates the emitter (212) area from both the base contact (236) and the extrinsic base (224), it is possible to provide improved base conductivity without generating peripheral transistor effects. The bipolar transistor (200) can be either N-P-N type or P-N-P type depending on the materials of fabrication, although high speed devices are typically of the N-P-N type.