Method of manufacturing a BiCMOS integrated circuit fully integrated within a CMOS process flow

摘要

A process for manufacturing a BiCMOS integrated circuit is implemented by adapting the masking and doping steps used in forming CMOS devices. Thus simultaneous formation of both CMOS and bipolar device structures eliminates the need for any additional masking or process steps to form bipolar device structures. Collector regions 20 of NPN transistors are formed simultaneously with N-wells 18. Collector regions of PNP transistors, if required, are formed simultaneously with P-wells 16. Base regions 24 of the bipolar transistors are formed using threshold voltage implant steps and/or lightly doped drain implant steps of PMOS transistors. Emitter regions 59 are formed, when using a single polysilicon CMOS process, simultaneously with the CMOS gates 72, 74. When employing a double polysilicon CMOS process, the emitter regions 59 are formed concurrently with the second polysilicon layer interconnect structure and/or source/drain regions 50,52 of NMOS transistors. For single polysilicon CMOS process, the buried layer regions 66 are formed during buried contact formation.