| 摘要 |
<p>A method for forming a BICMOS integrated circuit having MOS field effect transistors and bipolar junction transistors is disclosed. The process comprises first defining separate active areas, forming a gate dielectric layer and a first layer of polysilicon. This polysilicon is then selectively etched to form a plurality of equally-spaced first polysilicon members comprising the gates (33, 34) of the MOS transistors and the extrinsic base contacts (35) of the NPN transistors. After insulating the first polysilicon members, an additional layer of polysilicon is deposited over the substrate to replanarize the entire wafer surface. The additional layer of polysilicon is then etched to form a plurality of second polysilicon members (65, 66, 67, 68, 69). Impurities are diffused from the polysilicon members to form source/drain regions (73, 74, 75, 76) of the MOS transistors and the extrinsic base (81) and emitter (77) regions of the NPN transistors. The final processing steps include providing the interconnection of the MOS and NPN transistors. <IMAGE></p> |
