Marks Samuel D, Quan Peiyu, Liu Rui, Highland Matthew J, Zhou Hua, Kuech Thomas F, Stephenson G Brian, Evans Paul G
Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
Rev Sci Instrum. 2021 Feb 1;92(2):023908. doi: 10.1063/5.0039196.
Solid-phase epitaxy (SPE) and other three-dimensional epitaxial crystallization processes pose challenging structural and chemical characterization problems. The concentration of defects, the spatial distribution of elastic strain, and the chemical state of ions each vary with nanoscale characteristic length scales and depend sensitively on the gas environment and elastic boundary conditions during growth. The lateral or three-dimensional propagation of crystalline interfaces in SPE has nanoscale or submicrometer characteristic distances during typical crystallization times. An in situ synchrotron hard x-ray instrument allows these features to be studied during deposition and crystallization using diffraction, resonant scattering, nanobeam and coherent diffraction imaging, and reflectivity. The instrument incorporates a compact deposition system allowing the use of short-working-distance x-ray focusing optics. Layers are deposited using radio-frequency magnetron sputtering and evaporation sources. The deposition system provides control of the gas atmosphere and sample temperature. The sample is positioned using a stable mechanical design to minimize vibration and drift and employs precise translation stages to enable nanobeam experiments. Results of in situ x-ray characterization of the amorphous thin film deposition process for a SrTiO/BaTiO multilayer illustrate implementation of this instrument.
固相外延（SPE）和其他三维外延结晶过程带来了具有挑战性的结构和化学表征问题。缺陷浓度、弹性应变的空间分布以及离子的化学状态均随纳米级特征长度尺度而变化，并且在生长过程中敏感地依赖于气体环境和弹性边界条件。在典型的结晶时间内，SPE中晶体界面的横向或三维传播具有纳米级或亚微米级的特征距离。一台原位同步加速器硬X射线仪器能够在沉积和结晶过程中利用衍射、共振散射、纳米束和相干衍射成像以及反射率来研究这些特征。该仪器集成了一个紧凑的沉积系统，允许使用短工作距离的X射线聚焦光学元件。通过射频磁控溅射和蒸发源来沉积薄膜。沉积系统可控制气体气氛和样品温度。样品通过稳定的机械设计进行定位，以最小化振动和漂移，并采用精确的平移台来进行纳米束实验。SrTiO/BaTiO多层膜非晶薄膜沉积过程的原位X射线表征结果说明了该仪器的应用。
