Effect of Germanium Preamorphization Implant on Performance and Gate-Induced Drain Leakage in SiGe Channel pFET

Silicon-germanium (SiGe) channel pMOSFET is considered as a replacement for silicon channel device for 32-nm node and beyond, because of its lower threshold voltage and higher channel mobility. Lower SiGe bandgap makes gate-induced drain leakage (GIDL) important for low leakage, high threshold voltage device designs. In this letter, the effect of prehalo/LDD Ge preamorphization implant (PAI) on GIDL and performance is investigated using experimental data and simulations. Results suggest that GIDL reduction of ~40% is achieved without Ge PAI and the total OFF-state leakage (IOFF) is reduced by ~50% with a slight reduction in drive current (ION) and similar short-channel effects as compared with the case with PAI for same process conditions, which is not reported yet. The reduction in GIDL, and hence the improvement in I_ON/I_OFF ratio is because of elimination of end-of-range defects at the source/drain sidewall junction regions. It is also shown that a slight reduction in I_ON in the absence of Ge PAI is because of a small increase in the extrinsic series resistance.