| 摘要 |
Disclosed are embodiments of a method of fabricating a bipolar transistor with a self-aligned raised extrinsic base. In the method a dielectric pad is formed on a substrate with a minimum dimension capable of being produced using current state-of-the-are lithographic patterning. An opening is aligned above the dielectric pad and etched through an isolation oxide layer to an extrinsic base layer. The opening is equal to or greater in size than the dielectric pad. Another smaller opening is etched through the extrinsic base layer to the dielectric pad. A multi-step etching process is used to selectively remove the extrinsic base layer from the surfaces of the dielectric pad and then to selectively remove the dielectric pad. An emitter is then formed in the resulting trench. The resulting transistor structure has a distance between the edge of the lower section of the emitter and the edge of the extrinsic base that is minimized, thereby, reducing resistance.
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