Evaluation of SiGeC HBT Varactor using different Collector access and Base-Collector junction Configuration in BiCMOS technologies

This paper is focused on the evaluation of SiGeC HBT varactor in BiCMOS technologies. First, we compare a standard collector-base junction varactor with the contribution of specific collector between a low cost SiGeC HBT module. From this, we suggest new types of structure with no additional mask which allows to keep high quality factor and to have a wide tuning range (3:1) between standard diode P+/Nwell and HBT varactor with SIC implant.

I. Introduction

Development of wireless communications has led to an increase in RF components request. Varactors are key components in Voltage Controlled Oscillators (VCO's). The implementation of varactors in CMOS technologies has already been demonstrated with MOS or diode varactors [4]. We have explored the process sequence of the collector-base junction of the SiGeC hetero-structure NPN bipolar transistor (HBT) without additional mask.