Horizontal Current Bipolar Transistor With a Single Polysilicon Region for Improved High-Frequency Performance of BiCMOS ICs

A new horizontal current bipolar transistor (HCBT) with a single polysilicon region and a CMOS gate polysilicon near the n⁺ emitter region is integrated with CMOS technology with the addition of two or three masks (three or four masking steps) and a small number of additional fabrication steps. The single-poly HCBT with an optimized collector exhibits f_T and f_max of 51 and 61 GHz, respectively, and an f_TBV_CEO product of 173 GHz · V, which are the best reported HCBT characteristics to date and among the highest performance Si BJTs. An HCBT with only two additional masks to CMOS has f_T and f_max of 43 and 53 GHz, respectively, and an f_TSV_CEO product of 120 GHz · V. The developed innovative fabrication techniques enable a very low-cost BiCMOS platform for wireless communication circuits.