Effect of the channel thickness on the performance of implant-free quantum-well MOSFETs

2D Non-Equilibrium Green Function simulations of a quantum-well MOSFET have been carried out. We have investigated the impact of the channel thickness on the device performance. Devices with 5 nm, 4 nm, 3 nm and 2 nm channel thicknesses have been simulated. Due to the fact that the channel thickness is very small, the Γ, L valleys are included in the simulations. The decrease of channel thickness reduces electrostatic control and increases the threshold voltage. The change in threshold voltage when the channel thickness changes from 5 nm to 2 nm is equal to 0.4 V. The L valley contribution to the current increases with the decrease of the channel thickness, becoming as large as 25 % for a device with 2 nm channel thickness.