(Invited) In Depth Study of Ge Impact on Advanced SiGe PMOS Transistors

Abstract

By using the most advanced devices, simulations and electrical characterizations as well as physicochemical tools, this paper revisit the role of SiGe layers in the improvement of performances of pMOS transistors. It is shown that an additional interfacial dipole effect due to Ge diffusion in the gate stack interfacial oxide needs to be added to the change of band structures in order to explain the dependence of threshold voltage on SiGe composition. The mobility gain brought by these alloys is then investigated. The relative role of Ge concentration, strain, interface states and strain relaxation is then discussed in detail.