氮化铝压电薄膜的反应磁控溅射制备与性能表征

	氮化铝压电薄膜的反应磁控溅射制备与性能表征
	毕晓猛
学位类型	博士
导师	吴一辉
	2014-07
学位授予单位	中国科学院大学
学位专业	机械制造及其自动化
摘要	氮化铝（AlN）薄膜材料作为一种重要的III-V族化合物，具有高声波速、高压电性以及良好的化学稳定性等优点，使得AlN压电薄膜在高频声波谐振器、滤波器、传感技术等领域备受关注。反应磁控溅射可以实现高质量AlN压电薄膜的低温快速生长，所以，在实际应用中被广泛采用。但由于材料性能对工艺参数极为敏感以及压电薄膜性能表征等问题，使得该材料的高质量制备尚未形成标准工艺。本文围绕AlN压电薄膜反应磁控溅射制备方法及性能表征开展了以下研究：根据电介质的极化理论，研究了AlN材料晶体结构与材料内部极化的关系，分析影响AlN材料压电性的因素,同时，利用固体中的弹性波理论计算了不同偏振态下的声波沿AlN晶体各晶轴传播时的相速度,并得出c-轴取向AlN压电薄膜具有较高的压电性以及高纵波速波速的结论。为了获得提高AlN压电薄膜c-轴取向的途径，论文通过Berg模型对反应溅射过程氮气流量与其偏压关系进行了模拟，预测了靶材的工作状态。通过在硅衬底上制备AlN压电薄膜的系列实验，对影响该材料质量的重要工艺参数进行了深入细致的研究；通过以上研究可知，当靶材处于金属态与中毒态的过渡区域时，薄膜既可以获得较好质量，而且还可以维持一定的生长速率；借助于X射线衍射技术、扫描电子显微镜、原子力显微镜等手段，同时提出了一种新型的、更精准的测试模型，利用该模型和压电响应力显微镜等对AlN薄膜的压电性进行测试和验证，建立了可对不同制备条件下AlN压电薄膜的晶体结构与形貌的高准确表征的方法。对不同溅射工艺参数下制备的AlN压电薄膜晶体结构、表面形貌以及表面粗糙度的分析发现，在溅射功率为460W，溅射气压为3.0mTorr，氮气流量比为85%，薄膜生长温度为400℃时，可制备出 (002)择优取向的高质量AlN压电薄膜，薄膜(002)晶面摇摆曲线的半高宽(FWHM)优于1.7°；在对本文制备的AlN薄膜的压电性定量分析过程中，利用本文所提模型测得AlN薄膜的纵向压电常数：d33=4.22pm/V，该数值与通用方法测得的AlN薄膜的纵向压电常数之间的偏差小于5.7%，从而验证了本模型的合理性与准确性。
其他摘要	As one of the III-V components, the aluminum nitride (AlN) thin films have been widely used in high frequency acoustic resonators and filters as well as sensors due to its high acoustic velocity, excellent piezoelectricity and good chemical stability. High quality AlN piezoelectric thin films have been widely fabricated by the reactive magnetron sputtering with high growth rate in low temperature. However, the quality of the AlN films is very sensitive to the sputtering parameters, and the characterization of the AlN films is complicated, so there is no standard process for the fabrication of the high quality AlN thin films. In this dissertation, researches were done focusing on the fabrication and characterization the sputtered AlN thin films.The relationship between the polarization of the AlN and its crystal structure was investigated according to the polarization theory in dielectric materials, and analyzed the influence factor of the AlN piezoelectricity. Meanwhile, the velocities of the acoustic waves propagating along the crystal axis with different polarization were calculated based on the theory of elastic waves in solids, which draws the conclusion that the AlN has strong piezoelectricity and high longitudinal acoustic wave in the c-axis direction.To obtain the means for the improvement of the c-axis orientation of the AlN thin films, the Berg’s model was used to predict the relationship between the nitrogen flow rate and its partial pressure, which gives out the target mode during the sputtering. The influence of the main sputtering parameters on the material quality was studied by a series of experiments of AlN fabrication on the Si substrate. According to the researches above, high quality AlN thin films could be deposited at a contented growth rate with the target in the transition from metal to compound state.The AlN thin films were investigated by the X-ray diffraction (XRD), scanning electric microscopy (SEM) and the atom force microscopy (AFM). A much accurate model was proposed for the longitudinal piezoelectric coefficient (LPC) measurement of the AlN thin film using the piezoresponse force microscopy (PFM). The high accurate characterization methods for AlN thin films deposited under different sputtering parameters were set.After studying the influence of the sputtering parameters on the AlN thin film growth, highly c-axis oriented AlN thin film was fabricated with a sputtering power of 460W, a sputtering pressure of 3.0mTorr, a ratio for the nitrogen flow rate of 85% and a substrate temperature of 400℃, and the full width at half maximum (FWHM) of (002) plane for this AlN thin film is less 1.7°. To measure the the piezoelectricity of the AlN thin films, A value for the PLC is achieve by this new model with d33=4.22 pm/V. The deviation between the PLC value by our model and that by common method is < 5.7%, which proved the rationality and accuracy of our model.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/41389
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	毕晓猛. 氮化铝压电薄膜的反应磁控溅射制备与性能表征[D]. 中国科学院大学,2014.

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