Modelling of Surface Potential and Drain Current for Linearly Doped Short Channel nMOSFET with Lnner Fringing Field
Aatrayee Das, Prachi Agarwal, Subhra Sarkar, Sudeshna Mukherjee, Manash Chanda, Swapnadip De
Department of ECE, Meghnad Saha Institute of Technology, Kolkata, India
Ananalytical sub threshold drain current model for linear profile based Double Halo Dual Material Gate MOSFET (DHDMG) is proposed. It is based on quasi-Fermi potential and it incorporates the inner fringing field at the two ends of the device. An average doping concentration expression is used here. Unlike the drift-diffusion approach, no fitting parameter is required in this model. Gauss’ law is applied to a rectangular box covering the entire depletion layer depth. A pseudo-2D analysis of it is made in order to model the sub threshold surface potential. The results, thus obtained, are compared with a 2D device simulator DESSIS. The results from DESSIS almost match with that obtained from the proposed model. This ensures that the model is suitable for suppressing the short channel effects. The validity and usefulness of the proposed model is hence proved for circuit simulation of ULSI devices operating in 40 nm sub threshold regime.
Gauss’s Law; surface potential; drain current; channel engineering