PNP-type bipolar transistor manufacturing method

An integrated circuit NPN-type bipolar transistor, comprising:

• a collector formed by an N-type doped well that is laterally delimited by a shallow trench isolation;
• a layer of insulation extending over the shallow trench isolation and including a first opening;
• a base formed by an epitaxial P-type doped region within said first opening and in contact with a top of said N-type doped well, said epitaxial P-type doped region having an upper surface;
• an extrinsic base formed by a P-type doped polysilicon layer extending in contact with a top surface of the layer of insulation and in contact with the upper surface of the epitaxial P-type doped region, the P-type doped polysilicon layer including a second opening over the upper surface of the epitaxial P-type doped region;
• spacers protecting lateral surfaces of the second opening;
• an emitter formed by an epitaxial N-type region that includes a first portion that extends through an opening in the spacers to contact the upper surface of the epitaxial P-type doped region and a second portion that is laterally delimited by the spacers;
• wherein the extrinsic base includes, laterally offset from the emitter and spacers, a base contact surface.

An integrated circuit NPN-type bipolar transistor, comprising:

• a collector formed by an N-type doped well that is laterally delimited by a shallow trench isolation;
• a base formed by an epitaxial P-type doped region in contact with a top of said N-type doped well, said epitaxial P-type doped region having an upper surface;
• an extrinsic base formed by a P-type doped polysilicon layer extending over the shallow trench isolation and in contact with the upper surface of the epitaxial P-type doped region, the P-type doped polysilicon layer including an opening over the upper surface of the epitaxial P-type doped region;
• spacers protecting lateral surfaces of the opening;
• an emitter formed by an epitaxial N-type region that includes a first portion that extends through an opening in the spacers to contact the upper surface of the epitaxial P-type doped region and a second portion that is laterally delimited by the spacers;
• wherein the extrinsic base includes, laterally offset from the emitter and spacers, a base contact surface;
• a further N-type doped well formed in the N-type doped well of the collector;
• and
• a more heavily doped N-type region over and in contact with the further N-type doped well;
• wherein the more heavily doped N-type region is shallow trench isolated from the N-type doped well of the collector.