Numerical simulations have been performed to investigate the electronic transport through the Silicon (Si) channel of 4 terminal nano-MOS, namely, drain, source, top gate and bottom gate. In this paper, the thickness of silicon film channel is varied from 1.5nm, 3nm to 5nm with other structural dimensions remain unchanged. The simulation is carry-out at Room Temperature (RT). Three models will be presented ballistic transport using green’s function approach, ballistic transport using semi-classical approach and drift diffusion transport.