DEVELOPMENT OF GATED TRANSITION METAL NITRIDE FIELD EMITTER ARRAYS

我们研制了一种门控氮化Nb场发射阵列。其制备过程可分为两个主要工艺：氮化Nb覆盖发射极的制备和栅电极的制备。采用转移模法制作氮化Nb发射体，可以均匀地制备出发射极尖端。一组26个圆被转移到表面被氧化的硅衬底上。模具的形成是通过用氢氧化四甲胺进行各向异性腐蚀来完成的。模具的氧化在发射器和栅极之间提供了绝缘层，该绝缘层通过以下工艺附着。取下硅模后，在绝缘层上沉积钼栅电极。栅孔是用回刻法形成的。将所制作的器件安装在真空室中，并对其在高真空下的电子发射性能进行了评估。第一阶段的驱动电压为14V，在偶尔放电后，驱动电压增加到20V，除放电外，发射稳定。观察了发射模式，发现部分发射的电子入射到栅电极上。通过优化制备工艺，我们期望进一步改善发射性能。

We have developed a gated niobium nitride field emitter arrays. The fabrication process can be divided into two major processes : fabrication of emitter covered with niobium nitride and fabrication of gate electrode. We adopted the transfer mold technique to fabricate niobium nitride emitter, by which we can fabricate the emitter apex uniformly. A set of 26 circles were transferred to silicon substrate of which surface had been oxidized. Formation of the mold was performed by anisotropic etching with tetramethylammoniumhydroxide. Oxidation of the mold provide an insulating layer between emitter and gate, which was attached by the following process. After removal of silicon mold, we deposited molybdenum gate electrode onto the insulating layer. Gate aperture was formed by etching back method. The fabricated device was installed into a vacuum chamber and was evaluated its electron emission performance in high vacuum. The driving voltage was 14V at the first stage and after occasional discharges, it increased to 20V.Emission was stable except discharges. Emission pattern was observed and we found some portion of the emitted electrons was incident on the gate electrode. Optimizing the fabrication process, we expect further improved emission property.