Modeling the short-channel threshold voltage of a novel vertical heterojunction pMOSFET

Analytical modeling of the threshold voltage of a Si/sub 1-x/Ge/sub x//Si heterojunction pMOSFET has been performed using a quasi-two-dimensional (quasi-2-D) approach for the calculation of the potential. It is shown that the use of Si/sub 1-x/Ge/sub x/ in the source region leads to an improvement in the short-channel behavior of deep submicron pMOSFETs. The V/sub T/ roll-off can be substantially decreased by introducing a material dependent barrier between source and channel. Furthermore it will be proven that this advantage will become stronger when channel lengths are decreased toward the deep submicron regime.