Examination of Quantum Potential Coefficient in Quantum Drift Diffusion Model

Abstract

In this paper, we have investigated a quantum potential model in the quantum drift diffusion (QDD) model which allows to simulate quantum confinement effects in the inversion layer for advanced MOSFETs. The accuracy of the quantum potential model has been examined by comparing with the Schrodinger Poisson (SP) model which is able to simulate the quantum confinement effects with high accuracy. As a result, the quantum potential model shows quantum confinement effects of electron distributions in the inversion layer for an advanced MOSFET with a 1.5 nm gate oxide thickness. In addition, we have focused on the gate voltage dependence of the quantum potential coefficient in the quantum potential model. Electron densities calculated using the QDD model provide good accuracy in high gate voltage region. On the other hand, there is a discrepancy of electron densities using the QDD model comparing the SP model in subthreshold voltage region. It is found that the discrepancy comes from an assumption of constant model coefficient.