Patent ID: 6551891
Filing Date: 2003-04-22
Classification: H01L

Abstract:
A process for fabricating a bipolar transistor comprising the steps of:producing a base region comprising an extrinsic base and an intrinsic base; forming an insulating layer above the intrinsic base; etching an orifice in the insulating layer, the orifice etched with dimensions corresponding to dimensions of an emitter window and the orifice etched with vertical lateral edges; producing an emitter formed from an oxide block on the insulating layer formed above the intrinsic base, so that the oxide block comprises a narrower lower part extending into the orifice etched in the insulating layer, the oxide block comprises a wider upper part resting on the insulating layer, the wider upper part of the oxide block having vertical lateral walls, so that the vertical lateral edges of the orifice in the insulating layer is self-aligned with the vertical lateral walls of the wider upper part; and implanting dopants in the extrinsic base before the emitter is formed and after the production of the emitter window, so that dopants are implanted on either side of and at a predetermined distance from the vertical lateral boundaries of the emitter window, so that the extrinsic base is self-aligned with respect to the emitter window.