液氮冲击中锑化铟红外焦平面探测器(InSb IRFPAs)的形变研究对理解探测器结构设计可靠性、预测探测器耐冲击寿命具有重要意义.在系统分析液氮冲击结束时模拟得到的InSb IRFPAs形变分布与方向的基础上,提出了降温过程中累积热应变完全弛豫的设想,升至室温后的模拟结果重现了室温下拍摄的InSb IRFPAs典型形变分布特征.经分析认为室温下拍摄的InSb IRFPAs表面屈曲变形源于底充胶固化中引入的残余应力应变,变形幅度随降温过程逐步减弱,至77 K时完全消失,升温过程则依据弹性变形规律复现典型棋盘格屈曲模式.这为后续InSb IRFPAs结构设计、优化及耐冲击寿命预测提供了理论分析基础.
The deformation appearing in InSb infrared focal plane arrays (IRFPAs) as subjected to liquid nitrogen shock tests, is an important criterion to assess the reliability of the structure designed and to predict the number of thermal cycling after which no cracks appear in InSb IRFPAs. After analyzing both the deformation distribution and the deformation running directions appearing in InSb IRFPAs at 77 K, we assume that the thermal strain accumulated in the liquid nitrogen shock test is completely relaxed. Based on this assumption and according to the temperature rising curve, we may obtain the deformation distribution in InSb IRFPAs at room temperature, which is identical in the deformation charactristics to the photograph of InSb IRFPAs taken at room temperature. After comparing the simulated liquid nitrogen shock tests (which InSb IRFPAs experience), with its fabrication process, we can infer that the square checkerboard buckling pattern appearing in the top surface of InSb IRFPAs originates from the residual stress and strain generated in the process of insufficient cures. And the deformation amplitude decreases with decreasing temperature of InSb IRFPAs in the nitrogen liquid shock tests. At 77 K, the deformation amplitude reduces to zero. This state corresponds to our assumption, that the accumulated stress and strain disappears. When the temperature of InSb IRFPAs increases from 77 K to room temperature, the square checkerboard buckling pattern will reappear in the top surface of InSb IRFPAs. These findings are beneficial to the optimization of the structure of InSb IRFPAs and to the improvement of the number of thermal cycling experienced by InSb IRFPA without cracks generated from liquid nitrogen shock tests.