Base resistance scaling for SiGeC HBTs with a fully nickel-silicided extrinsic base

A novel SiGeC HBT process with a quasi-self-aligned emitter-base architecture and a fully nickel-silicided extrinsic base region has been developed. A very low total base resistance R/sub B/ was achieved along with simultaneous NiSi formation on the polycrystalline emitter and collector regions. Uniform silicide formation was obtained across the wafer, and the resistivity of the Ni(SiGe:C) silicide layer was 24 μ/spl Omega//spl middot/cm. About 50-100 nm of lateral growth of silicide underneath the emitter pedestal was observed. DC and HF results with balanced f
_T
/f
_max
values of 41/42 GHz were demonstrated for 0.5×10μm
²
transistors.