Method of forming BiCMOS devices having mosfet and bipolar sections therein

Claim 1

A method for manufacturing a BiCMOS device on a semiconductor substrate having an MOSFET section and a bipolar section comprising the steps of: forming a first region of a first conductive type in the MOSFET section and a second region of a second conductive type in the bipolar section; forming a first insulating layer on the surface of the first and the second regions; forming a collector region having the second conductive type and an intrinsic base region having the first conductive type in the second region; depositing a first polysilicon layer doped with impurities of the second conductive type, a first oxide film and a first nitride film on a top portion of the first insulating layer sequentially; patterning the first nitride film, the first oxide film and the first polysilicon layer simultaneously to form a gate pattern in the MOSFET section and an emitter pattern above the intrinsic base region of the bipolar section; implanting ions of the second conductive type into the first region to form lightly-doped regions in the first region; forming sidewalls respectively on lateral sides of the gate pattern and the emitter pattern; implanting ions of the second conductive type into the first region to form a source and a drain regions; implanting ions of the first conductive type into the intrinsic base region to form an extrinsic base region; performing oxidation process to form a second oxide film on the first and the second regions; removing the first nitride film and the first oxide film of the gate pattern and the emitter pattern; removing the first polysilicon layer of the emitter pattern and the first insulating layer below the emitter pattern; depositing a second polysilicon layer doped with impurities of the second conductive type on the whole top surface of the MOSFET section and the bipolar section; forming an emitter region by diffusing the impurities doped in the second polysilicon layer into the intrinsic base region; and patterning the second polysilicon layer to form a first gate electrode made of the first and the second polysilicon layers in the MOSFET section and the first emitter electrode contacting the emitter region in the bipolar section.

Claim 2

A method for manufacturing a BiCMOS device on a semiconductor substrate having an MOSFET section and a bipolar section comprising the steps of: forming a first region of a first conductive type in the MOSFET section and a second region of a second conductive type in the bipolar section; forming a first insulating layer on the surface of the first and the second regions; forming a collector region having the second conductive type and an intrinsic base region having the first conductive type in the second region; depositing a first polysilicon layer doped with impurities of the second conductive type, a first oxide film and a first nitride film on a top portion of the first insulating layer sequentially; patterning the first nitride film, the first oxide film and the first polysilicon layer simultaneously to form a gate pattern in the MOSFET section and an emitter pattern above the intrinsic base region of the bipolar section; implanting ions of the second conductive type into the first region to form lightly-doped regions in the first region; forming sidewalls respectively on lateral sides of the gate pattern and the emitter pattern; implanting ions of the second conductive type into the first region to form a source and a drain regions; implanting ions of the first conductive type into the intrinsic base region to form an extrinsic base region; performing oxidation process to form a second oxide film on the first and the second regions; removing the first nitride film and the first oxide film of the gate pattern and the emitter pattern; removing the first polysilicon layer of the emitter pattern and the first insulating layer below the emitter pattern; depositing a second polysilicon layer doped with impurities of the second conductive type on the whole top surface of the MOSFET section and the bipolar section; forming an emitter region by diffusing the impurities doped in the second polysilicon layer into the intrinsic base region; and patterning the second polysilicon layer to form a first gate electrode made of the first and the second polysilicon layers in the MOSFET section and the first emitter electrode contacting the emitter region in the bipolar section.