压电半导体非线性断裂失效分析的广义本征分解法研究

Piezoelectric semiconductor is very sensitive to cracks, holes, inclusions and other defects which occur in the process of manufacture, polarization and during the service. Fracture and failure analysis of Piezoelectric semiconductor should be a typical strong nonlinear problem, analysis for this kind of problem are very difficulty due to the fracture and failure influence by and the nonlinear introduced by contact boundary conditions, compound production mechanism of carriers and the un-ignored temperature field. We will propose Proper Generalized Decomposition method for the analysis of the Piezoelectric semiconductor, and by using this Proper Generalized Decomposition method, we will analyze fracture and failure influence by the contact boundary conditions, compound-production mechanism of carriers and the temperature field of the piezoelectric semiconductors. Through this project, the stress intensity factor, electric displacement intensity factor，electric current intensity factor and the heat flux intensity factor also the energy release rate are investigated; fracture test of piezoelectric semiconductors under the temperature field are launched. We will find out the influence mechanism for the nonlinear constitutive relationship, contact boundary conditions, compound-production of carriers for the piezoelectric semiconductors, and give the nonlinear fracture criterion for piezoelectric semiconductors, which aim to provide theoretical analysis and technical support for the evaluation of the service life and reliability analysis of piezoelectric semiconductor devices by the study of this project.

压电半导体对制造、极化和使用过程中产生的裂纹、孔洞、夹杂等缺陷非常敏感。压电半导体的断裂失效本质上是一个典型的强非线性问题，但接触边界条件、载流子复合-产生机制以及不可忽视的温度场对压电半导体断裂失效带来的非线性使得这类问题的分析求解异常困难。本项目通过研究压电半导体非线性断裂失效的广义本征分解方法，利用广义本征分解法分析压电半导体非线性断裂失效的应力强度因子、电位移强度因子、载流子浓度强度因子和热流强度因子以及能量释放率，开展压电半导体的温度场断裂测试试验, 分析接触边界条件、载流子复合-产生机制以及温度场对压电半导体的非线性断裂失效的影响。探讨压电半导体非线性断裂失效准则，为压电半导体器件的寿命分析和可靠性评估提供理论分析及技术支撑。

压电半导体的接触边界条件以及不可忽视的温度场对压电半导体断裂失效带来很大的影响，本项目从理论、数值、实验三方面研究了压电半导体的温度场等带来的非线性断裂问题, 分析了接触边界条件对断裂的影响,研究了压电半导体断裂分析的广义本征分解方法及表面变质层机械性能的表征理论与方法。在该项目资助下，取得了以下成果：1）利用广义Almansi定理及算子理论获得包括机械载荷、电载荷、载流子及热载荷等广义载荷下的普通解。根据不连续位移-边界元数值方法，获得裂纹面上的应力和热流强度因子。研究了均匀和线性变化热载荷对三维横观各向同性压电半导体断裂的影响； 2）针对压电半导体的接触问题，采用COMSOL有限元计算软件，分别在压电半导体线性和非线性本构关系下，进行金属-压电半导体接触问题的数值分析，针对肖特基和欧姆接触边界条件分析接触区域的载流子密度分布、电势分布以及载流子集中分布情况。分析了肖特基和欧姆两种接触对裂纹面广义不连续位移及裂纹尖端广义应力强度因子的影响，探讨不同接触边界条件下压电半导体非线性断裂失效。3）搭建了压电半导体热力电耦合加载实验装置，测试不同温度下压电半导体的断裂韧性，探索温度场变化对压电半导体断裂韧性的影响规律。研究温度场下压电半导体断裂失效问题，为探讨压电半导体非线性断裂失效准则提供实验基础。4）研究压电半导体断裂失效的广义本征分解方法，进而利用广义本征分解法分析非线性断裂失效的应力强度因子、电位移强度因子、载流子浓度强度因子。为快速开展压电半导体非线性断裂分析数值分析提供计算手段。5）提出了压电半导体涂层及金属基表面变质层机械性能的剥层压痕试验方法，利用拉伸法及压痕试验方法表征了表面变质层的弹性模量、屈服强度、硬化指数及断裂韧性等。为开展金属-压电半导体接触的性能分析提供试验基础。