Authors: T.A. Fjeldly, S. Kolberg and B. Iñíguez
Affilation: Norwegian University of Science and Technology, Norway
Pages: 668 - 673
Keywords: MOSFET, double gate, modeling, conformal mapping
In nanoscale double gate MOSFETs, the dependence on the bias voltages of the 2D electron barrier topology in the conducting channel is all-important for the operation of the device. We consider a DG MOSFET with a gate length of 25 nm and a silicon thickness of 12 nm, for which the electrostatics, the electron distribution, and the device current are modeled in all regimes of operation. In subthreshold, the modeling is based on solving the Laplace equation for the rectangular DG MOSFET body, using conformal mapping techniques. For this case, a precise, analytical 2D potential profile is obtained throughout the body in terms of elliptic integrals, including the full dependency of the applied terminal voltages. In strong inversion, an analytical solution of Poisson’s equation is adopted. The solutions for the two regimes are combined in a self-consistent model, from which both the drift-diffusion and the ballistic/quasi-ballistic currents are obtained for the full range of device bias voltages. Both classical and quantum mechanical approaches have been developed. The modeling results obtained for potential and charge distributions and for the current agree very well with numerical simulations.