Patent ID: 7132344

Claim:
A bipolar junction transistor (BJT) structure that includes a self-aligned emitter contact, and wherein the BJT structure includes an N+ collector buried layer formed at an upper surface of a semiconductor substrate, an N-type collector epitaxial layer formed on the buried layer, a dielectric isolation structure that extends from the upper surface of the epitaxial layer to the buried layer to define a BJT active device region and an N+ sinker diffusion region formed in the BJT active device region to extend from the upper surface of the epitaxial layer to the buried layer, the BJT structure further comprising: a field plate trench formed in the BJT active device region to surround a collector well region of the epitaxial layer and extending from the upper surface of the epitaxial layer to the buried layer; field plate polysilicon formed in the field plate trench and separated from the epitaxial layer and the buried layer by intervening dielectric material, the field plate polysilicon extending above the upper surface of the epitaxial layer; P-type base conductive material formed on the upper surface of the collector well region, the P-type base conductive material being formed to be in contact with the field plate polysilicon; and an N-type conductive emitter formed to be in contact with the base conductive material, the emitter being separated from the field plate polysilicon by intervening dielectric material.