Patent ID: 7572708
Filing Date: 2009-08-11
Classification: H01L

Abstract:
1. A bipolar transistor structure comprising; a collector region formed in a semiconductor substrate, the collector region having a first conductivity type; a base region formed over the collector region, the base region having a second conductivity type that is opposite the first conductivity type; a first layer of dielectric material formed directly on an upper surface of the base region and having a first emitter window opening formed therein, the first emitter window opening defining sidewalls of the first layer of dielectric material that extend from an upper surface of the first layer of dielectric material to an upper surface of the base region to expose an upper surface area of the base region; a second layer of dielectric material formed on the first layer of dielectric material and having a second emitter window opening formed therein that is aligned with the first emitter window opening, the second emitter window opening defining sidewalls of the second layer of dielectric material that extend from an upper surface of the second layer of dielectric material to an upper surface of the first layer of dielectric material to expose a perimeter surface area of the first layer of dielectric material that extends around the perimeter of the first emitter window opening; doped silicate glass spacers formed on the sidewalls of the second layer of dielectric material and on the exposed perimeter surface area of the first layer of dielectric material and extending to a perimeter edge of the first emitter window opening; and a conductive emitter having the first conductivity type and formed to extend into the first and second emitter window openings and into contact with the doped silicate glass spacers, the sidewalls first layer of dielectric material and the exposed upper surface area of the base region.