基于多孔Al_2O_3绝缘层的MIM电子源电子发射特性研究  

Emission Characteristics of Novel Metal-Insulator-Metal Emitter with Porous Al_2O_3 Insulation Layer

作　　者：薛涛[1] 张小宁[1] 刘纯亮[1] 

机构地区：[1]西安交通大学电子物理与器件教育部重点实验室,西安710049

出　　处：《真空科学与技术学报》2015年第11期1390-1395,共6页Chinese Journal of Vacuum Science and Technology

基　　金：国家自然科学基金项目(No.61372018)

摘　　要：针对基于无孔Al_2O_3绝缘层的金属-绝缘层-金属(MIM)电子源存在显著负阻效应和无法在气氛下稳定发射电子的特点,提出并制备了一种Al底电极-多孔Al_2O_3绝缘层-Ti/Au复合顶电极结构的MIM电子源。在真空,不同压强的氮气和空气中的电子发射结果表明,Al_2O_3绝缘层经过磷酸扩孔后,MIM电子源的负阻效应在电子发射区间几乎消失,同时增强了电子发射的局部电场,电子获得更好的加速,提高了发射电流。Ti/Au复合顶电极改善了Au膜和多孔Al_2O_3绝缘层的电接触,减小了电子能量的散射。该电子源发射的电子能够激发氮气,在空气和氮气中的发射电流大小受气体及其压强的影响。A novel metal-insulator-metal （MIM） emitter was developed to reduce the negative resistance and en- hance the emission stability of the conventional MIM emitter in gas ambient. The newly-developed MIM emitter consists of the A1 bottom-electrode, porous A1203 layerand Au/Ti top-electrode. The porous A1203 layer, synthesized by anodic oxida- tion of the magnetron sputtered M-coating, was etched with phosphoric acid to widen the pores. The impact of the mi- crostructures of porous A1203 and Ti/Au top-electrode on the emission characteristics was investigated with scanning elec- tron microscopy, atomic force microscopy, and field emission measurementin vacuum and at different pressures of N2 and air. The results show that the novel MIM emitter significantly increases the emission current and considerably reduces the negative resistance, possibly because of the increases of localized field enhancement factor and surface roughness, and be- cause of a decrease of electron scattering energy. Depending on the pressure of air and/or N2, the emission current is ca- pable of exciting N2 molecules.

关 键 词：多孔Al2O3 MIM电子源 电子发射特性 负阻效应 

分 类 号：O462.4[理学—电子物理学] TN104.3[理学—物理]