High-Mobility P-Type MOSFETs with Integrated Strained-Si_0.73Ge_0.27 Channels and High-\kappa/Metal Gates

Strained-Si_0.73Ge_0.27 channels are successfully integrated with high-\kappa /metal gates in p-type metal-oxide- semiconductor field effect transistors (pMOSFETs) using the replacement post-gate process. A silicon cap and oxide inter layers are inserted between Si_0.73Ge_0.27 and high-\kappa dielectric to improve the interface. The fabricated Si_0.73Ge_0.27 pMOSFETs with gate length of 30 nm exhibit good performance with high drive current (\sim428 \muA/μm at V_\rm DD=1 V) and suppressed short-channel effects (DIBL\sim 77 mV/V and SS\sim90 mV/decade). It is found that the enhancement of effective hole mobility is up to 200% in long-gate-length Si_0.73Ge_0.27-channel pMOSFETs compared with the corresponding silicon transistors. The improvement of device performance is reduced due to strain relaxation as the gate length decreases, while 26% increase of the drive current is still obtained for 30-nm-gate-length Si_0.73Ge_0.27 devices.