脉冲偏压电弧离子镀基体沉积温度的计算与纳米多层硬质薄膜的初步研究

【作者】 白晓；

【导师】 林国强；

【作者基本信息】 大连理工大学 ， 材料加工工程， 2004， 硕士

【摘要】 基体沉积温度是离子镀工艺中影响薄膜性能和限制可镀基体范围的最重要参数之一。与传统的以直流负偏压为基础的电弧离子镀（direct current bias arc ion plating，DCAIP）相比，脉冲偏压电弧离子镀技术（pulsed-bias arc ion plating，PBAIP）不仅能够有效降低沉积温度，适合于具有较低的回火温度或应力释放温度点的基体材料；同时，在相同沉积温度下，PBAIP技术中利用脉冲偏压和占空比等电参数的优化组合可以改善薄膜性能。但是，目前对于PBAIP技术中沉积温度的降低及工艺参数对沉积温度的影响还缺乏系统认识，如果能够通过计算来预测不同工艺参数下的沉积温度，达到通过工艺参数的调整来实现控制沉积温度的目的，对于薄膜的性能优化、基体材料的选择和沉积工艺的合理设计都具有重要意义。 PBAIP与DCAIP的不同在于基体偏压的作用形式，本文从脉冲偏压的作用形式出发，用实验的方法分析了脉冲偏压电参数的特点，得到了近方波的相对规范形状的偏压偏流输出波形。同时详细探讨影响沉积温度的各因素对沉积温度的影响趋势及影响程度，分析表明：离子轰击、基体的热辐射、通过基体支撑轴的热传导散热是影响基体沉积温度的主要因素。在此基础之上，基于基体获得能量与释放能量相平衡原则，建立包含离子轰击功率密度、辐射功率密度、热传导功率密度、材料的比热容、质量及面积和温度变化等参量的温度计算模型。最后以沉积TiN为例，用实测的沉积温度对计算模型进行检验，在-1000～0V的偏压范围内理论与实验得到了好的吻合。对模型的进一步理论分析表明，脉冲偏压工艺降低沉积温度的本质在于其离子能量输入密度是相同偏压幅值下直流偏压工艺能量输入密度的D（占空比D＜1）倍；在既定设备和基体上，通过脉冲工艺电参数可以实现对沉积温度的有效控制。 脉冲偏压电弧离子镀温度控制和低温沉积机制的明确为在硬质合金等基体上制备纳米多层硬质薄膜奠定了基础。本文以Ti／TiN为例，采用间歇送人N₂的方法，制备纳米多层薄膜，展开PBAIP技术纳米多层薄膜的初步研究，为优化沉积工艺，制备纳米多层硬质薄膜提供基本实验依据。经分析证明，利用一定时间间隔送入N₂的工艺可以实现Ti／TiN纳米多层薄膜的制备；脉冲偏压电弧离子镀制备的调制周期为100nm左右的Ti／TiN多层薄膜的结合力和显微硬度，与常规直流和脉冲工艺下的TiN均质膜相比，有大幅度提高，结合力可达90N，显微硬度在Hk3000kgf／mm²左右。通过调整Ti／TiN薄膜的调制周期和周期比，制备了具有超硬特性的Ti／TiN多层薄膜，显微硬度最高可达Hk4799 kgf／mm²；分析表明，引起纳米多层薄膜硬的提高的原因可能有两个，一是Hall-Petch关系的晶粒细化效应，二是由于位错源在层间产生和运动受到抑制所致。更多还原

【Abstract】 The substrate temperature is one of most important factors, which influence the properties of films and substrate. Compared with Direct Current Bias Arc Ion Plating(DCAIP), Pulsed-bias Arc Ion Plating(PBAIP) not only can decrease the substrate temperature efficiently , but also can be applied in the substrate whose temperature of temper or stress is very low; further more, at the same deposition temperature, the properties of films can be improved by the optimal combination between the bias voltage and duty cycle in PBAIP. However, till now there is no systemic report in why the substrate temperature can be decreased and how the temperature can be influenced by the electric parameters in PBAIP. If the substrate temperature can be predicted or controlled by adjusting the parameters, it is significant to improve the films properties, broaden the range of substrate material, or design the reasonable deposition techniques.There is a difference in bias voltage on substrate between Arc Ion Plating(AIP) and Pulsed-bias Arc Ion Plating(PBAIP). The bias voltage of substrate in PBAIP has been analyzed by experiments and its wave profile is basically rectangle. The factors, which influence the substrate temperature, are discussed in detail and the results shows that the substrate temperature is mainly decided by ion bombardment, heat radiation, heat conductivity. On the basis of energy conversation principle, a model of substrate temperature incorporates power density of ion bombardment, heat radiation and heat conductivity in PBAIP when the bias voltage varies from -1000V to 0 has been established, and experimental tests are also conducted to verify the calculation and a good agreement is observed between calculated results and experimental results. From analyzing the calculation model of substrate temperature, it is found that the input power density of PBAIP is only D(duty cycle, D<1) times as one in DCAIP and the temperature can be controlled efficiently by adjusting the parameters such as bias-voltage or duty cycle in PBAIP.Based on mechanism of the low substrate temperature controlled by technique parameters, multilayers can be deposited on alloy by PBAIP. In this paper, by infusing N2 to chamber periodically, Ti/TiN multilayers are produced. The results shows that nano-multilayers cae be deposited by infusing N2 periodically in PBAIP, combination force is about 90N and micro-hardness is about Hk 3000 kgf/mm2 when the modulation structure is 100nm.These properties are better than TiN films produced in PBAIP. The Ti/TiN multiplayer with super hardness has been deposited by adjusting the modulation period, and the maximum of hardness is 4799 kgf/mm2. There are two reasons in improving the hardness of films., one is the refining effect of the grain size, the other is that dislocations are blocked when moving among the layers.更多还原