复合尖锥场发射阵列研究

发布时间：2018-01-12 20:25

本文关键词：复合尖锥场发射阵列研究　出处：《电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：Spindt型场发射阵列具有可在室温下工作、启动速度快、稳定性强、低功耗和发射电流密度高等优点,在平板显示器、行波管和传感器等许多领域都有着重要地位,一直是国内外研究的热点。目前常见的Spindt型尖锥场发射材料有钼(Mo)和硅(Si)等,但这些材料都存在逸出功较高及易损坏等问题。六硼化镧(LaB6)具有低逸出功、耐高温与性质稳定等特点,是一种优良的场发射材料,但与硅衬底的附着力不足。另外,由于镀膜存在不均匀性,阵列中尖锥的形状各不相同,场发射电流可能存在很大差异,部分尖锥的发射电流过大时容易产生打火现象,这将损毁尖锥并造成栅阴的短路,甚至导致阵列失效。论文的主要研究内容包括:1、在传统Spindt型场发射阵列的基础上,结合前人的工作,设计出一种复合尖锥结构,先沉积Mo过渡台阶,再在台阶上制备LaB6尖端,将两种材料的特性结合起来,降低逸出功的同时增大了尖锥的附着力。另外在尖锥底部加入了一层硅电阻层,电阻层起到分压作用,可以使不同尖锥的电流发射更加均匀,减少异常发射和打火现象,还能起到过流保护的作用,提高场发射阵列的工作稳定性。2、通过氧化、光刻和离子刻蚀等方法,在单晶硅基片上制作出直径和高度各1μm、间距5μm、总面积1×1mm2的栅孔阵列;再采用蒸发镀膜技术,依次沉积硅电阻层、铝牺牲层、Mo过渡台阶和LaB6尖端;使用稀磷酸水浴法将牺牲层剥离后,即得到复合尖锥场发射阵列。3、在场发射阵列的制备过程中仍存在一些问题,如栅极和薄膜的开裂、尖锥的脱落、材料氧化和表面毛刺等,本文针对这些现象进行了一系列后处理,包括退火、烧氢和老炼工艺等,结果表明这些工艺能够解决相应问题,增强了阵列的场发射性能。4、搭建电路,设计基片支架,对所得阵列进行了场发射性能测试和稳定性测试,在180V的栅极电压下,器件的最高发射电流超过8mA,电流密度达0.8A/cm2,发射也较为稳定,论证了本课题工艺的可行性。
[Abstract]:The Spindt field emission array has the advantages of high starting speed, high stability, low power consumption and high emission current density, which can work at room temperature. Traveling wave tube (TWT) and sensor are very important in many fields, and they have been the research hotspot at home and abroad. At present, the common materials of Spindt type conical field emission are molybdenum (Mo) and SiSi (Si) and so on. However, these materials have the problems of high escape power and easy damage. Lanthanum hexaboride LaB6) is an excellent field emission material with the characteristics of low escape power, high temperature resistance and stable properties. But the adhesion to silicon substrate is not enough. In addition, due to the inhomogeneity of the coating, the shape of the tip cone in the array is different, and the field emission current may be very different. When the emission current of some cone is too large, it is easy to produce fire phenomenon, which will damage the tip and cause the short circuit of the grid negative, even lead to the array failure. The main research contents of this paper include: 1. On the basis of the traditional Spindt field emission array and combined with the previous work, a composite conical structure was designed, which deposited Mo transition step first, and then prepared the LaB6 tip on the step. The characteristics of the two materials are combined to reduce the escape power and increase the adhesion of the tip cone. In addition, a layer of silicon resistance layer is added to the bottom of the tip cone, which plays a role of partial voltage. It can make the current emission of different cone more uniform, reduce the abnormal emission and fire phenomenon, also can play the role of over-current protection, improve the stability of the field emission array. 2, through oxidation. By photolithography and ion etching, a gate hole array with a diameter and a height of 1 渭 m ~ 2, a distance of 5 渭 m ~ 2 and a total area of 1 脳 1 mm ~ 2 was fabricated on the monocrystalline silicon substrate. Then the silicon resistance layer, the aluminum sacrificial layer, the transition step and the LaB6 tip were deposited by evaporative coating technology. After the sacrificial layer is stripped by dilute phosphoric acid bath, the composite cone field emission array. 3. There are still some problems in the fabrication of the field emission array, such as the crack of the gate and film, and the shedding of the tip cone. In this paper, a series of post-treatment, such as annealing, hydrogen burning and aging process, have been carried out to deal with these phenomena. The results show that these processes can solve the corresponding problems. The field emission performance of the array is enhanced by .4. the circuit is built, the substrate bracket is designed, and the field emission performance and stability of the array are tested under the grid voltage of 180V. The maximum emission current is more than 8 Ma, the current density is 0.8 A / cm ~ 2, and the emission is relatively stable. The feasibility of this process is demonstrated.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304

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