Energy band structure of quantum-size metal-oxide-semiconductor field effect transistor

We have investigated the energy band structure of the 40 nm gate length n-metal-oxide-semiconductor field effect transistor (MOSFET) recently fabricated by M. One, M. Saito, T. Yoshitomi, C. Fiegna, T. Ohguro and H. Iwai (IEEE Transaction on Electron Devices 42: 1822 (1995)). By the classical particle picture, the conducting channel at zero gate bias is already open. When the one-dimensional quantum effect along the sample growth direction is included, the semiclassical model gives an increased threshold voltage. It is shown here that the large measured threshold voltage and therefore the success of a short-length MOSFET working at room temperature are well explained when the three-dimensional quantization effect is included. (C) 1997 Academic Press Limited.