Effects of N2-content on formation behavior in AlN thin films studied by NEXAFS: Theory and experiment
Effects of N2-content on formation behavior in AlN thin films studied by NEXAFS: Theory and experiment
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DOI：
10.1016/j.jallcom.2020.156128
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发表时间：
2020-12-05
影响因子：
6.2
通讯作者：
Bootchanont, Atipong
中科院分区：
文献类型：
--
作者：
Supruangnet, Ratchadaporn;Sailuam, Wutthigrai;Bootchanont, Atipong
本文采用反应射频磁控溅射法在载玻片上制备了AlN薄膜，并在不同的N2/（Ar + N2）流量比（N2/（Ar + N2））为20%、40%、60%和80%的混合气氛下制备了AlN薄膜。X射线衍射（XRD）研究表明，当N-2/（Ar + N-2）为60%和80%时，纤维锌矿-AlN的（0002）晶面为。相比之下，具有20%和40%的N-2/（Ar + N-2）的样品由于载玻片上的AlN晶体结构的低水平而不能显示出（0002）面的清晰峰。而氮K边的近边X射线吸收精细结构（NEXAFS）谱反映了薄膜生长过程和晶体形成初期局部环境的演化。将计算结果与用FEX 9程序和第一性原理计算得到的NEXAFS谱进行了比较，其中采用密度泛函理论（DFT）计算形成能。实验和计算之间的形成机制显示出良好的一致性。AlN薄膜在低和高N2/（Ar + N2）比下分别沿a、b和c轴沿着择优取向。这一结果也证实了与表面形貌观察原子力显微镜和扫描电镜。(C)2020爱思唯尔B. V.保留所有权利。
In this work, AlN thin films were deposited on glass slides by a reactive-radio frequency (RF) magnetron sputtering with various mixed ambient of N-2/(Ar + N-2) flow ratio at 20%, 40%, 60% and 80%. X-ray diffraction (XRD) investigation showed (0002) plane of wurtzite-AlN for 60% and 80% of N-2/(Ar + N-2). In contrast, samples with 20% and 40% of N-2/(Ar + N-2) could not exhibit the clear peak of the (0002) plane because of the low level of AlN crystal structure on glass slides. However, the near edge X-ray absorption fine structure (NEXAFS) spectra at nitrogen K-edge showed the evolution of thin film growth and local environment at the initial state of crystal's formation. The results were compared with calculated NEXAFS spectra obtained from the FEFF9 program and first-principles calculations, in which the density functional theory (DFT) was employed to calculate formation energy. An excellent agreement between the experiment and calculation on the formation mechanism was revealed. The AlN thin films were seen to exhibit a preferred orientation along the a, b-axis and the c-axis at low and high N-2/(Ar + N-2) ratio of ambient gas, respectively. This result was also confirmed with the surface morphology observed by AFM and SEM. (C) 2020 Elsevier B.V. All rights reserved.