Self-aligned bipolar npn transistor with 60 nm epitaxial base

A self-aligned double-poly bipolar transistor with a low-temperature epitaxial base is presented. Selective epitaxy emitter window technology (SEEW) is used to demonstrate the leverage of an epitaxial base technology by achieving 60-nm basewidth, an 7.5-kΩ/sq. intrinsic base sheet resistance, a peak current gain up to 115, and a C-B breakdown voltage of 7.5 V. Despite the low intrinsic base sheet resistance, a peak transit frequency of 30 GHz has been calculated for the transistor. Further, the advantages of SEEW technology for submicron emitters and very thin base formation are explained.