Kosiel K, Dominik M, Ściślewska I, Kalisz M, Guziewicz M, Gołaszewska K, Niedziółka-Jonsson J, Bock W J, Śmietana M
Instytut Technologii Elektronowej, Al. Lotników 32/46, 02-668 Warsaw, Poland.
Nanotechnology. 2018 Apr 3;29(13):135602. doi: 10.1088/1361-6528/aaa9a3.
This paper presents an investigation of properties of selected metallic oxides deposited at a low temperature (100 °C) by atomic layer deposition (ALD) technique, relating to their applicability as thin overlays for optical fiber sensors resistant in alkaline environments. Hafnium oxide (Hf O with y/x approx. 2.70), tantalum oxide (Ta O with y/x approx. 2.75) and zirconium oxide (Zr O with y/x approx. 2.07), which deposition was based, respectively, on tetrakis(ethylmethyl)hafnium, tantalum pentachloride and tetrakis(ethylmethyl)zirconium with deionized water, were tested as thin layers on planar Si (100) and glass substrates. Growth per cycle (GPC) in the ALD processes was 0.133-0.150 nm/cycle. Run-to-run GPC reproducibility of the ALD processes was best for Hf O (0.145 ± 0.001 nm/cycle) and the poorest for Ta O (0.133 ± 0.003 nm/cycle). Refractive indices n of the layers were 2.00-2.10 (at the wavelength λ = 632 nm), with negligible k value (at λ for 240-930 nm). The oxides examined by x-ray diffractometry proved to be amorphous, with only small addition of crystalline phases for the Zr O . The surfaces of the oxides had grainy but smooth topographies with root-mean square roughness ∼0.5 nm (at 10 × 10 μm area) according to atomic force microscopy. Ellipsometric measurements, by contrast, suggest rougher surfaces for the Zr O layers. The surfaces were also slightly rougher on the glass-based samples than on the Si-based ones. Nanohardness and Young modules were 4.90-8.64 GPa and 83.7-104.4 GPa, respectively. The tests of scratch resistance revealed better tribological properties for the Hf O and the Ta O than for the Zr O . The surfaces were hydrophilic, with wetting angles of 52.5°-62.9°. The planar oxides on Si, being resistive even to concentrated alkali (pH 14), proved to be significantly more alkali-resistive than AlO. The Ta O overlay was deposited on long-period grating sensor induced in optical fiber. Thanks to such an overlay the sensor proved to be long-lasting resistant when exposed to alkaline environment with a pH 9. Thereby, it also proved that it has a potential to be repeatedly reused as a regenerable optical fiber biosensor.
本文介绍了通过原子层沉积（ALD）技术在低温（100°C）下沉积的选定金属氧化物的性能研究，涉及它们作为碱性环境中耐光纤传感器薄涂层的适用性。分别以四（乙基甲基）铪、五氯化钽和四（乙基甲基）锆与去离子水为基础沉积的氧化铪（y/x约为2.70的HfO）、氧化钽（y/x约为2.75的TaO）和氧化锆（y/x约为2.07的ZrO），作为平面Si（100）和玻璃基板上的薄层进行了测试。ALD过程中的每循环生长（GPC）为0.133 - 0.150 nm/循环。ALD过程的逐次运行GPC再现性对于HfO最佳（0.145±0.001 nm/循环），对于TaO最差（0.133±0.003 nm/循环）。这些层的折射率n为2.00 - 2.10（在波长λ = 632 nm处），k值可忽略不计（在240 - 930 nm的λ处）。通过X射线衍射测定法检测的氧化物被证明是无定形的，ZrO仅添加了少量晶相。根据原子力显微镜，氧化物表面具有颗粒状但光滑的形貌，均方根粗糙度约为0.5 nm（在10×10μm区域）。相比之下，椭偏测量表明ZrO层的表面更粗糙。基于玻璃的样品表面也比基于Si的样品表面略粗糙。纳米硬度和杨氏模量分别为4.90 - 8.64 GPa和83.7 - 104.4 GPa。耐刮擦性测试表明，HfO和TaO的摩擦学性能优于ZrO。表面是亲水性的，润湿角为52.5° - 62.9°。Si上的平面氧化物即使对浓碱（pH 14）也具有抗性，被证明比AlO更耐碱。TaO涂层沉积在光纤中诱导的长周期光栅传感器上。由于这样的涂层，该传感器在暴露于pH 9的碱性环境时被证明具有持久的抗性。因此，它也被证明有潜力作为可再生光纤生物传感器被重复使用。
