In-Depth Study of Quantum Effects in SOI DGMOSFETs for Different Crystallographic Orientations

We have used simulation to characterize quantum mechanical effects in undoped double-gate metal-oxide-semiconductor field-effect transistors for different substrate crystallographic orientations. Their influence on the inversion-charge calculation for devices with different oxide and silicon layer thicknesses has been analyzed for all the operation regimes. In the subthreshold regime, bias-induced quantization effects (BQEs) can be neglected since only size-induced quantization effects are important, although these could be neglected for silicon layers thicker than 20 nm. A simple model has been proposed in this case for the calculation of the quantum inversion charge, using the classical charge as starting point. BQEs are important only above threshold; however, they can generally be neglected for oxide layers thicker than 2 nm.