EOT Scaling of ${\rm TiO}_{2}/{\rm Al}_{2}{\rm O}_{3}$ on Germanium pMOSFETs and Impact of Gate Metal Selection

${\rm TiO}_{2}/{\rm Al}_{2}{\rm O}_{3}/{\rm Ge}$ gate stacks have promising characteristics for future germanium-channel high-performance MOSFETs. In this letter, ${\rm TiO}_{2}/{\rm Al}_{2}{\rm O}_{3}$ bilayer high-k dielectrics with EOT 0.65 nm are demonstrated and used in Ge pMOSFETs for the first time, giving low subthreshold swing (71 mV/dec) and large on-state current (28 A/um). In addition, detailed investigations of these devices with two different gate metals—Al/W and Al/Pt—are performed for stable metal/ ${\rm TiO}_{2}$ interfaces and EOT scaling.