The Study Of Modeling Of 2D Model Of VD-MOSFET Parasitic On Resistance

With the rapidly development of science and technology,electronic products service in every corner of our life,and the semiconductor components is the core of these electronic products.VD-MOSFET has important status in the field of energy control and control switch at least 50%of the world's electricity consumption because of excellent electrical performance such as low driving power,high input impedance,good frequency characteristic and fast switching speed.Due to the breakdown voltage of power devices cannot be excessive low or high,high on resistance will cause high energy consumption and temperature which will affect the stability of component performance.So choose the optimal structure and doping concentration of VD-MOSFET is particularly important.Basic principles of VD-MOSFET which need us to conduct a comprehensive understanding,the accurate physical model has very important significance for the study of its characteristics.The literature shows that the current research for power semiconductor on resistance model is still in the stage of slowly development,both early S.C.SUN approximation model and the later model established by the conformal mapping,are not really gives the accurate analytical solution of on resistance.This article will focus on the on resistance of VD-MOSFET,according to the current flow characteristic,build the parasitic on resistance model,then lists the Laplace's equation and boundary condition equations.This paper can be summarized as the following several parts:Firstly,understanding the VD-MOSFET features,summarize about modeling on resistance method and solving process,compared the advantages of several kinds of research methods.The methods including analytical method,numerical method and semi-analytical method.Secondly,modeling the 2D VD-MOSFET parasitic on resistance.The model structure is divided into region ?(electronic accumulation layer),region ?(JFET area),region ?(N drift area)and region ?(substrate area)according to the resistance characteristics.Analysis the carrier motion law of each regional then the state equation and boundary conditions were determined.Because of VD-MOSFET has different doping concentration among the regions,it is necessary to define doping concentration of each region,and set connection conditions between them.To solve the analytic equation of electric potential by the Separation variable method and Fourier orthogonal transformation method,and the resistance of the model can be got at last.Finally,validated the electric potential distribution and the resistance of the part that out channel of VD-MOSFET on resistance based on the semi-analytical method by the finite difference method,fully demonstrated the correctness of 2D model be proposed.Calculation results show that the error of semi-analytical method for two-dimensional model of the electric potential distribution and numerical calculation of the electric potential distribution difference is very small and the electric potential is stable as a whole.The difference between 2D resistance model proposed and numerical calculation resistance are tiny,errors are below 1%.Finally,the Resistance error that based on the semi-analytic method under different parameters is very small,which is less than 1%.In this paper,the process to solve the 2D potential equation by the semi-analytical method is accurate,and it has a high value for the research of VDMOSFET parasitic on resistance model.