RF Performance Optimization of SiGe:C Transistors via Ge-B Doping Strategies and RTP

This paper focuses on the optimization of Germanium and Boron profiles at the epitaxial SiGe:C layer of a self-aligned SiGe:C transistor structure with 0.13 mu m emitter width as well as the last significant thermal step (RTP) which follows the in-situ phosphorus doped poly-Si deposition of the emitter electrode. At first, critical process steps affecting the doping profile at the base such as emitter epitaxy, selective implant of collector (SIC) and the last RTP (950 degrees C, 5 seconds) have been conserved and 6 different Germanium and Boron doping strategies were applied at the 250 angstrom SiGe:C epitaxial growth which is followed by a 150 nm Si-CAP deposition. The epi-growth strategy with the best RF performance outcome was chosen for further optimization with the RTP step. As a result of these two successive optimizations, simulated transistors exhibit f(t), f(max), BVceo and beta of 192GHz, 211GHz, 2.09V and 1195 respectively.