Sanford N A, Blanchard P T, White R, Vissers M R, Diercks D R, Davydov A V, Pappas D P
National Institute of Standards and Technology, Physical Measurement Laboratory, Division 686, 325 Broadway, Boulder, CO 80305, United States.
National Institute of Standards and Technology, Physical Measurement Laboratory, Division 686, 325 Broadway, Boulder, CO 80305, United States.
Micron. 2017 Mar;94:53-65. doi: 10.1016/j.micron.2016.12.001. Epub 2016 Dec 21.
Laser-assisted atom probe tomography (L-APT) was used to examine superconducting TiN/Ti/TiN trilayer films with nominal respective thicknesses of 5/5/5 (nm). Such materials are of interest for applications that require large arrays of microwave kinetic inductance detectors. The trilayers were deposited on Si substrates by reactive sputtering. Electron energy loss microscopy performed in a scanning transmission electron microscope (STEM/EELS) was used to corroborate the L-APT results and establish the overall thicknesses of the trilayers. Three separate batches were studied where the first (bottom) TiN layer was deposited at 500°C (for all batches) and the subsequent TiN/Ti bilayer was deposited at ambient temperature, 250°C, and 500°C, respectively. L-APT rendered an approximately planar TiN/Si interface by making use of plausible mass-spectral assignments to N, SiN, and SiO. This was necessary since ambiguities associated with the likely simultaneous occurrence of Si and N prevented their use in rendering the TiN/Si interface upon reconstruction. The non-superconducting TiN phase was also revealed by L-APT. Neither L-APT nor STEM/EELS rendered sharp Ti/TiN interfaces and the contrast between these layers diminished with increased film deposition temperature. L-APT also revealed that hydrogen was present in varying degrees in all samples including control samples that were composed of single layers of Ti or TiN.
激光辅助原子探针断层扫描技术（L-APT）被用于检测标称厚度分别为5/5/5（纳米）的超导TiN/Ti/TiN三层膜。这类材料对于需要大量微波动态电感探测器阵列的应用来说很有意义。这些三层膜通过反应溅射沉积在硅衬底上。在扫描透射电子显微镜（STEM/EELS）中进行的电子能量损失显微镜分析被用于证实L-APT的结果并确定三层膜的总厚度。研究了三个不同批次的样品，其中第一个（底部）TiN层在500°C下沉积（所有批次均如此），随后的TiN/Ti双层分别在室温、250°C和500°C下沉积。L-APT通过对N、SiN和SiO进行合理的质谱归属，呈现出近似平面的TiN/Si界面。这是必要的，因为与Si和N可能同时出现相关的模糊性使得在重建时无法利用它们来呈现TiN/Si界面。L-APT还揭示了非超导TiN相。L-APT和STEM/EELS都没有呈现出清晰的Ti/TiN界面，并且随着薄膜沉积温度的升高，这些层之间的对比度降低。L-APT还表明，所有样品（包括由单层Ti或TiN组成的对照样品）中都不同程度地存在氢。
