脉冲偏压电弧离子镀大颗粒净化的理论与实验研究

【作者】 郭慧梅；

【导师】 林国强；

【作者基本信息】 大连理工大学 ， 等离子体物理， 2004， 硕士

【摘要】 本文改进和完善了脉冲偏压电弧离子镀的大颗粒净化的理论模型，系统研究了脉冲偏压作用下的等离子体鞘层的物理特性和大颗粒在鞘层中的充电、受力以及运动行为，从理论上给出脉冲偏压工艺对于大颗粒净化效应的合理解释；对在不同工艺下制备的TiN薄膜样品进行了实验观测和分析，得到薄膜的表面形貌和大颗粒的数量及尺寸分布情况，得到了与计算预见相吻合的实验结果，为大颗粒净化的物理模型提供了佐证。 在脉冲偏压电弧离子镀技术的开发中，该模型保证在不明显降低沉积效率的前提下，对得到洁净表面高质量薄膜的工艺优化，有重要指导作用。 具体完成了如下工作： (1)大颗粒净化模型的完善 对黄美东博士等建立的大颗粒净化模型进行了进一步的改进和完善，对大颗粒在鞘层中的充电和受力进行了定量的计算，考虑了离子拖拽力的影响。 (2)脉冲偏压鞘层的物理特性 采用Edelberg和Aydil的无碰撞鞘层模型，以实验中所得的基体偏压数据作为边界条件，计算得到在不同的脉冲偏压下鞘层中的电势分布、鞘层厚度、鞘层中的电子、离子平均速度和离子密度。 (3)大颗粒在鞘层中的充电、受力和运动 利用鞘层中大颗粒表面的充电平衡条件，计算得出大颗粒表面电势，进而得到大颗粒所带电量，并对大颗粒在鞘层中受到电场力、离子拖拽力和重力等进行计算。 计算表明，大颗粒在脉冲偏压鞘层中始终带负电，但是电量随着靠近基体而不断的减少；在大部分鞘层区域内，电场力大于离子拖拽力脉冲偏压电弧离子镀大颗粒挣化的理论与实验研究和重力之和，故而可能使大颗粒不落到基体上。这是大颗粒能够被净化的理论依据。(4)试验结果 采用JSM一5600LV型扫描电镜观察在不同工艺制度下制备的TIN薄膜样品表面形貌，然后将得到的SEM图片输入Qso0IW型图像分析仪，对大颗粒的尺寸分布及面密度进行统计分析。 结果表明脉冲偏压对大颗粒有明显的净化作用，即薄膜表面比直流偏压下大颗粒尺度和数量都少得多，其净化效果随不同的脉冲参数组合有很大的差别，而且主要反映在小尺度颗粒的净化效果。偏压幅值越高，占空比越大(在一定范围内)，净化效果越好。(5)工艺实践 应用大颗粒净化的物理模型在正交实验基础上进行优化选择，得到净化效果达54%的优化工艺，该工艺满足合成Ti/TIN纳米多层超硬薄膜的要求。更多还原

【Abstract】 In this paper the academic mode of decontamination of Mps is improved and perfected. The characteristic of pulsed bias sheath ,charge forces and motion of Mps in sheath are studied systemically. A logical explainer of Mps’ decontamination under pulsed bias is given theoretically. TiN film samples from different craftwork are observed and analyzed. Configuration of film surface and MPs quantity and dimension are obtained. Analysis and statistic indicate that the experimental result is in accord with calculation result. So it can be proved that the academic mode is correct.In the development of PBAIP our mode give important instruction for gaining clean surface and enhancing film quality on the premise of that aggradations efficiency is not fallen evidently. The idiographic work:(1) Perfection of the mode of MPs decontamination perfectionThe decontamination mode of Dr Meidong Huang’s is improved and perfected. Charge and forces on Mps are calculated quantitatively, ion drag force is considered.(2) Pulsed-Bias sheath characteristicThe collisionless sheath mode of Edelberg and Aydil is adopted. The datum come from experiment are regarded boundary condition, voltage distribution in sheath, thickness of sheath, ion and electrons density in sheath are all studied.(3) Charge, forces and motion of Mps in sheathMaking use of the charge balance condition the surface potential of MPs can be gained. Then the charge is obtained. Ion drag force, electric force and gravitation are calculated.It is indicated that the charge on Mps is always negative in the sheath but is reducing when Mps close with electrode. At most region of sheath electric force is greater than the summation of ion drag force and gravitation, so Mps may deviate from electrode. This is the academic gist of Mps decontamination.(4) Experimental resultJSM-5600LV model scanning electron microscope is used to observe the surface morphologies of film come from different craftwork. Then the SEM photos are put into Q500IM model picture analyzer, Mps dimensional distribution and surface density are analyzed statistically.It is indicated that the film surface under pulsed biases is cleaner than the film surface under dc biases. The pulsed parameters are influential to film surface. Little dimensional Mps are cleansed more easily. Voltage and duty cycle are greater the effect is better. (5) Craftwork practiceOn the base of mode and cross experiment the optimized craftwork is obtained, decontaminative impact is 54%. The craftwork meets the request of composing nanometer multiplayer films of Ti/TiN.更多还原