Numerical Simulation Of Piezoelectric Semiconductor Structures

With the development of lightweight,energy saving and environmental protection,the new energy vehicles have become the trend of future development,which put forward higher requirements for the automotive electric drive system.A new generation of piezoelectric semiconductor materials GaN and ZnO because of its high band gap,high breakdown electric field,high mobility,is more and more concerned by car manufacturers.However,the research on the mechanical,mechanical and physical properties of piezoelectric semiconductor materials is relatively small,which leads to the lack of theoretical guidance for the reliability design of piezoelectric semiconductor devices.In this paper,the mechanical and physical properties of piezoelectric semiconductor structures are studied by numerical simulation.The main works are as follows:1)According to the constitutive relation,governing equations and boundary conditions of piezoelectric semiconductor,the basic equations are linearized and a "piezoelectric-conductor" numerical iterative method is proposed.For the reliability problems in engineering,the iterative method is used to analyze the problem of I type crack plane piezoelectric semiconductor,the effects of various loads on the strength factor are given.2)Based on the rigorous fundamental equations of p iezoelectric semiconductors,nonlinear piezoelectric semiconductor structure is studied.Firstly,considering the carrier recombination-generation process,the effects of different mechanisms are compared;secondly,according to the nonlinear constitutive equation of piezoelectric semiconductor,the discrepancy of linearized and nonlinearized constitutive on the plane fracture is discussed;finally,for two different boundary conditions,ohmic contact and schottky contact,the influence of different boundary conditions on the results is analyzed.3)For the typical structure of pn-junction interface problem,the formation process of the built-in potential is studied.Through the analysis of interface crack in pn-junction,the distribution of the physical quantities of the piezoelectric semiconductor at the interface crack tip and the influence of the built-in potential on the intensity factor are studied.