Hot-Carrier and Fowler-Nordheim (FN) Tunneling Stresses on RF Reliability of 40-nm PMOSFETs With and Without SiGe Source/Drain

In this brief, RF reliabilities of hot-carrier and Fowler-Nordheim (FN) tunneling stresses on 40-nm PMOSFETs with and without SiGe source/drain (S/D) are studied and compared in detail. The results show that even the strained device with SiGe S/D has a better RF performance; however, its RF reliabilities after both hot-carrier and FN tunneling stresses are deteriorated remarkably by strain-induced defects. In addition, because the SiGe S/D strain-induced defects are mostly located at the surface of the extension of S/D, but not at the channel, the degradation difference between the strained and nonstrained PMOSFETs becomes less as the stress changes from the hot carrier (gate stress voltage V gstr = drain stress voltaged V dstr )to the vertical-only, i.e., the FN tunneling stress(V dstr = 0 but with some V gstr ).