LaB6复合型场发射阵列阴极的结构设计

摘要

In order to improve the operation stability of traditional Spindt field emission array cathode, a novel structure of lanthanum hexaboride (LaB6) composite field emission array cathode is proposed, which includes an amorphous silicon resistance layer, a molybdenum transition layer, and a lanthanum hexaboride emitter layer. The influences of the thickness of the resistive layer, the transition layer, and the emitter layer on the thermal stress field distribution of the cathode are simulated by ANSYS and the results of simulation are verified by experiments. Simulation results show that the thickness of the resistive layer does not affect the distribution of the thermal stress field, but only changes the value of the thermal stress. The maximum thermal stress of the cathode decreases as the thickness of the resistive layer increases. The transition layer can effectively alleviate the thermal stress of the emission layer, and its thickness affects the field distribution of thermal stress. As a result, the optimum parameters are as follows: a-Si layer thickness is 72 nm, Mo layer thickness is 200 nm, and LaB6layer thickness is 728 nm. The thermal stress test results of the films are consistent with the simulation results, which proves the feasibility of reducing the thermal stress by introducing the transition layer and the resistive layer.%为了提高传统Spindt型场发射阵列阴极的稳定性,提出了一种新型的LaB6复合型场发射阵列阴极结构,该结构包括非晶硅电阻层、钼过渡层和六硼化镧发射体层.基于ANSYS平台模拟了该阴极中电阻层、过渡层和发射体层厚度对热应力场分布的影响,并根据仿真结果进行了实验验证.仿真结果表明,电阻层厚度不影响热应力场的分布,只是改变热应力的大小;随着电阻层厚度的增加,阴极最大热应力会减小;过渡层可以有效减缓发射层的热应力,且过渡层的厚度会影响热应力场的分布;当电阻层厚度为72 nm,过渡层厚度为200 nm,发射层厚度为728 nm时,阴极最为稳定.薄膜热应力测试结果与模拟结果基本一致,证实了引入过渡层和电阻层对于减小阴极热应力的可行性.