Method for fabricating a trench bipolar transistor

摘要

A bipolar transistor formed in a trench depression such that a single impurity diffusing step is effective to form a buried collector layer electrically connected to a vertical collector conductor. The lateral diffusion forming the vertical collector conductor is effective to form the conductor with a uniform vertical doping profile, thereby reducing non-uniform series collector resistance characteristics. A trench depression sidewall dielectric is formed, and the trench is filled with a transistor silicon material by a selective epitaxial process. Base and emitter region are then formed in the collector epitaxial material.