Implementation of Automatic Differentiation to Python-based Semiconductor Device Simulator

A Python-based device simulator named Impulse TCAD was developed. The simulator is built on top of a nonlinear finite volume method (FVM) solver. To describe physical behavior of non-standard materials, both device properties and their dominant equations can be customized. The given FVM equations are solved by the Newton method, where required derivatives of the equations are derived automatically by using an automatic differentiation technique. As a demonstration, a steady state analysis of the negative capacitance field effect transistors with ferroelectric materials is selected, where the coupled Poisson and Devonshire equations are implemented in several different ways.