Patent ID: 11908898
Assignee: GLOBALFOUNDRIES U.S. INC.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 15:
16. A method of forming a lateral bipolar transistor structure, the method comprising:
forming a semiconductor layer on an insulator;
forming an emitter/collector (E/C) layer on the semiconductor layer, the E/C layer having a first doping type;
forming a first base layer on the semiconductor layer and horizontally adjacent the E/C layer, the first base layer having a second doping type opposite the first doping type and the first base layer including:
an upper portion having a first horizontal width from the E/C layer,
a lower portion under the upper portion and having a second horizontal width from the E/C layer less than the first horizontal width, and
a sidewall adjacent the E/C layer including a concave surface, and

forming a second base layer on the first base layer and adjacent a spacer, the second base layer having the first doping type, wherein the upper portion of the first base layer separates a lower surface of the second base layer from the E/C layer.