Hydrodynamic simulation of electron heating in conventional and lightly‐doped‐drain MOSFETs with application to substrate current calculation

Abstract

SUMMARYThis paper reviews the state of the art in hydrodynamic simulation of hot-carrier transport in semiconductor devices with application to MOSFET substrate current calculation. Hydrodynamic equations for semiconductors and derived and discretized expressions of these equations for device simulation are presented. Special attention has been given to the discretization of the input power term that appears in the energy conservation equation. A new discretization method for the input power term, based on power generation consideration, is proposed. Energy-based physical models for mobility and impact ionization are described for use in hydrodynamic simulation. Simulation results for both conventional and lightly-doped-drain MOSFETs are presented.

Hydrodynamic Device Simulationwith New State Variables Specially Chosen fora Block Gummel Iterative Approach

“…Below we present the new state variables; the detailed methodology used to determine them is motivated by transforming the conventional steady state 2-dimensional HD equations [3,4], into forms which are nearly self-adjoint.…”

Three‐Dimensional Hydrodynamic Modelingof MOSFET Devices

“…[4] resolves the non-convergence issues of the CC and EB equations individually; however, difficulties remain in the convergence of the overall system when using a block-Gummel solution method. Recognizing that the convergence of the entire system of equations was the problem, some researchers suggested that the input energy term is the root of the nonconvergence problem [6,7]. In particular, the numerical problems were thought to be caused by the implicit dependence of the current density on the carrier temperature [7].…”

“…However, by not consistently using the SG-discretized expression for current density, this scheme underestimates the input energy. Here, a vector identity is used in the discretization, following [4,6,8]. In this work, the effect of the discretization of the RTA term on convergence is investi-…”