Method of fabricating a semiconductor structure having MOS and bipolar devices

摘要

A method of fabricating a semiconductor structure (10) having MOS and bipolar devices includes providing an isolation structure having MOS and bipolar active areas including doped wells (28,30) . A collector region (56) is formed in the bipolar active area well (28B) and a first semiconductor layer (62) is then formed over the MOS and bipolar active areas. An active base region (66) is formed in the bipolar active area well (28B) and a dielectric layer (68,70) is formed on the first semiconductor layer (62) over a portion of the bipolar active area. A window (72) is formed through the dielectric layer (68,70) and extends to the first semiconductor layer (62). A second semiconductor layer (86) is then formed over the MOS and bipolar active areas. A gate electrode (88) is formed on the MOS active area and emitter (92) and collector (94) electrodes are formed on the bipolar active area. The gate (88), emitter (92) and collector (94) electrodes are formed from both the first (62) and second (86) semiconductor layers and the emitter electrode (92) extends into the window (72). After doping the emitter (92) and collector (94) electrodes, self-aligned source and drain regions (108) are diffused into the MOS active area and an emitter region (110) is diffused into the bipolar active area from the emitter electrode (92) through the window (72).