Narrow base transistor and method of fabricating same.

摘要

There is provided a method for use in the fabrication of a bipolar narrow base transistor including the steps of : providing a substrate of semiconductor material including a region (14) of first conductivity type forming the collector of the transistor; forming a first layer (32) of second conductivity type epitaxial semiconductor material over the region; forming a second layer (36) of second conductivity type epitaxial semiconductor material over the first layer, the second layer of a relatively higher dopant concentration than the first layer; oxidizing a portion of the second layer to form an insulating layer (38); and removing the oxidized portion of the second layer to expose a portion of the first layer (32). As a result, the extrinsic base region (36) is laterally spaced from emitter region (58), the exposed portion of the first layer (32) forming the intrinsic base region. The steps of forming the first and second layers are preferably performed using low temperature, ultra-high vacuum, epitaxial deposition processes.