Hybrid-integrated lateral bipolar transistor and CMOS transistor and method for manufacturing the same

A semiconductor device in which a lateral bipolar transistor and a CMOS transistor are hybrid-integrated,

• the lateral bipolar transistor including:
• an open region opened in a device isolating oxide film surrounding an active region;
• a polysilicon film formed on the open region and having such a thickness as to expose the active region out of the polysilicon film;
• an intrinsic base region of the lateral bipolar transistor;
• and
• a protective film covering at least part of a peripheral surface of the active region exposed by opening the open region in the device isolating oxide film and having a thickness of 6 to 8 angstrom;
• a collector diffusion layer formed in the active region;
• and
• a collector electrode directly connected to the collector diffusion layer region,
• wherein the protective film is located on between the polysilicon film and the intrinsic base region.

A semiconductor device comprising a lateral bipolar transistor,

• the lateral bipolar transistor including:
• a substrate including a first conductive layer;
• an active region located on the first conductive layer and having such a shape as to protrude from the first conductive layer and have an upper surface and at least one side surface in contact with the upper surface;
• an open region opened in a device isolating oxide film surrounding the active region;
• a polysilicon film formed on the open region;
• an emitter region solid-phase diffused from the polysilicon film;
• and
• a dummy gate polysilicon formed in the device isolating oxide film and having an upper surface which is located above the upper surface of the active region,
• wherein an upper surface of the active region is located above an upper surface of the emitter region.

A method for manufacturing a semiconductor device in which a lateral bipolar transistor and a CMOS transistor are hybrid-integrated, the method comprising the steps of:

• forming an extrinsic base region for externally connecting a base region of an active region of the lateral bipolar transistor, following a step of at least one time of ion implantation in which an impurity is implanted with the gate electrode of the CMOS transistor used as a mask;
• forming an open region around the active region by removing a predetermined portion of a device isolating oxide film surrounding the active region;
• forming an intrinsic base region of the lateral bipolar transistor by implanting ions in a region of a side surface of the active region exposed by the formation of the open region partially overlapping with the extrinsic base region;
• forming a protective film for protecting the active region during etching in a subsequent step on a surface of the active region;
• forming an impurity-containing polysilicon film in a region including the active region in which the protective film is formed and the open region in the protective film formation step;
• etching away the polysilicon film by a predetermined thickness;
• and
• forming an emitter diffusion layer region and a collector diffusion layer region by solid-phase diffusing an impurity from the impurity-containing polysilicon film left after etching in the polysilicon etching step.

A method for manufacturing a semiconductor device in which a lateral bipolar transistor and a CMOS transistor are hybrid-integrated, the method comprising the steps of:

• forming an extrinsic base region for externally connecting a base region of an active region of the lateral bipolar transistor, following a step of at least one time of conductive film formation in which an impurity is implanted with the gate electrode of the CMOS transistor used as a mask;
• forming an open region around the active region by removing a predetermined portion of the device isolating oxide film surrounding the active region;
• forming an intrinsic base region of the lateral bipolar transistor by implanting ions in a region of a side surface of the active region exposed by the formation of the open region partially overlapping with the extrinsic base region;
• forming a protective film for protecting the active region during etching in a subsequent step on a surface of the active region;
• forming an impurity-containing polysilicon film in a region including the active region in which the protective film is formed and the open region in the protective film formation step;
• etching away the polysilicon film by a predetermined thickness;
• forming an emitter diffusion layer region by solid-phase diffusing an impurity from the impurity-containing polysilicon film left after etching in the polysilicon etching step;
• forming a collector diffusion region in the active layer;
• and
• forming an electrode directly connected to the collector diffusion layer region.

A method for manufacturing a semiconductor device including a lateral bipolar transistor, wherein a step of manufacturing the lateral bipolar transistor includes the steps of:

• forming an active region having such a shape as to protrude from a first conductive layer and have an upper surface and at least one side surface in contact with the upper surface on the first conductive layer serving as a substrate;
• opening an open region in the device isolating oxide film surrounding the active region;
• forming a polysilicon film on the open region;
• forming an emitter region by solid-phase diffusing the emitter region from the polysilicon film;
• and
• forming a dummy gate polysilicon in the device isolating oxide film,
• and the shape of the emitter region solid-phase diffused from the polysilicon film is controlled by the dummy gate polysilicon.