Study Of The Stress Effect On Flexible Radio-frequency Silicon Diodes And Switches Under Bending Conditions

With the development of science and technology,flexible electronics is coming into sight for its unique advantages.Flexible electronics is a technology that with electronic and circuit made on flexible substrate,and it can be used under different bending conditions for a variety of application scenarios.With the deepening of research on flexible electronics,the working frequency of flexible electronics is also increasing.Compared with the traditional hard electronics,flexible electronics is becoming more and more competitive and will be an important field of electronics industry in the future.Flexible electronics is in the primary stage,and not produced to large scale for its uncertain stability.In order to solve this problem and meet the demand of curved working occasion,the bending stress of flexible electronics is researched,and the related effects are also analyzed.It is an effective method to study the stress effect of the flexible RF electronic devices by the reliable finite element analysis simulation.This paper reports the modeling and stress simulation of flexible single crystal silicon nanomembrane diodes and switches with cylindrical bending,by the finite element analysis software ABAQUS.It has been found that different simulation software,the quality of mesh partition and load precision affect the result and accuracy of simulation.With the device bending radius decreasing(e.g.77.5/38.5/28.5/21 mm),the stress of the devices becomes larger(178/357/492/601 MPa,respectively).As the size of the device becomes larger,the stress becomes larger.The thin SU-8-2 layer has little effect on the stress simulation(less than 5 MPa).The S21 parameter of the devices becomes larger and RF characteristics changed better as the stress increase with the bending direction in this research.The stress of 80 ?m2 diode under the bending radius of 21 mm is 110 MPa larger and the S parameter is 0.15 dB larger that of 38.5 mm.On the current direction,the stress contributes to the hole mobility,and the resistance and series parasitic resistance is reduced,resulting higher S21 parameters.These results and analysis will provide theoretical guidance to the size design and stability of flexible electronics in the future.