Kim Yun Young
School of Mechanical Engineering, Chungnam National University, Daejeon 34134, Korea.
Materials (Basel). 2022 Mar 15;15(6):2165. doi: 10.3390/ma15062165.
Nanoscale amorphous silicon carbide (a-SiC) thin films are widely used in engineering applications. It is important to obtain accurate information about their material properties because they often differ from those of the bulk state depending on the fabrication technique and process parameters. In this study, the thermal and mechanical properties of a-SiC thin films were evaluated using the femtosecond pump-probe technique, which provides high spatial and temporal resolutions sufficient to measure films that have a thickness of less than 300 nm. a-SiC films were grown using a plasma-enhanced chemical vapor deposition system, and the surface characteristics were analyzed using ellipsometry, atomic force microscopy, and X-ray reflectometry. The results show that the out-of-the-plane thermal conductivity of the films is lower than that of bulk crystalline SiC by two orders of magnitude, but the lower limit is dictated by the minimum thermal conductivity. In addition, a decrease in the mass density resulted in a reduced Young's modulus by 13.6-78.4% compared to the literature values, implying low Si-C bond density in the microstructures. The scale effect on both thermal conductivity and Young's modulus was not significant.
纳米级非晶碳化硅（a-SiC）薄膜在工程应用中广泛使用。获取有关其材料特性的准确信息很重要，因为根据制造技术和工艺参数，它们的特性往往与块状状态不同。在本研究中，使用飞秒泵浦-探测技术评估了a-SiC薄膜的热性能和力学性能，该技术提供了足够高的空间和时间分辨率，足以测量厚度小于300 nm的薄膜。使用等离子体增强化学气相沉积系统生长a-SiC薄膜，并使用椭偏仪、原子力显微镜和X射线反射仪分析表面特性。结果表明，薄膜的面外热导率比块状晶体SiC低两个数量级，但下限由最小热导率决定。此外，质量密度的降低导致杨氏模量比文献值降低了13.6-78.4%，这意味着微观结构中的Si-C键密度较低。热导率和杨氏模量的尺寸效应不显著。
