Young’s modulus, Poisson’s ratio, and residual stress and strain in (111)-oriented scandium nitride thin films on silicon
Young’s modulus, Poisson’s ratio, and residual stress and strain in (111)-oriented scandium nitride thin films on silicon
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DOI：
10.1063/1.2217106
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发表时间：
2006-07
影响因子：
3.2
通讯作者：
M. Moram;Z. Barber;C. Humphreys;T. Joyce;P. Chalker
中科院分区：
文献类型：
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作者：
M. Moram;Z. Barber;C. Humphreys;T. Joyce;P. Chalker
采用分子束外延技术，以氨气为反应性氮源，在硅衬底上生长了225 nm厚的氮化钪外延膜。ScN相对于Si的主要晶向为（111）ScN <$（111）Si和[1-10]ScN <$[0-11]Si;然而，在薄膜中也存在一些孪晶。由于生长过程中吸附原子的迁移率较低，薄膜呈柱状，表面粗糙。在优化条件下生长的ScN薄膜的无应变晶格常数为4.5047± 0.0005 A，用高分辨X射线衍射（HRXRD）测定。随后使用HRXRD评估面内和面外应变，并用于确定ScN沿着111方向的泊松比，发现其为0.188±0.005。进行晶片曲率测量并结合应变信息来确定膜的平均杨氏模量，发现其为270± 25 GPa。残余薄膜应力范围为-1至1GPa（取决于薄膜生长温度和温度）。
Epitaxial scandium nitride films (225nm thick) were grown on silicon by molecular beam epitaxy, using ammonia as a reactive nitrogen source. The main crystallographic orientation of ScN with respect to Si is (111)ScN‖(111)Si and [1–10]ScN‖[0–11]Si; however, some twinning is also present in the films. The films displayed a columnar morphology with rough surfaces, due to low adatom mobility during growth. The strain-free lattice parameter of ScN films grown under optimized conditions was found to be 4.5047±0.0005A, as determined using high-resolution x-ray diffraction (HRXRD). In-plane and out-of-plane strains were subsequently evaluated using HRXRD and were used to determine the Poisson ratio of ScN along the ⟨111⟩ direction, which is found to be 0.188±0.005. Wafer curvature measurements were made and combined with the strain information to determine the average Young’s modulus of the films, which is found to be 270±25GPa. Residual film stresses ranged from −1to1GPa (depending on film growth temperature an...