Area-selective bottom-up synthesis routes of thin films are required to overcome the current limits in lithography, and such growth can be achieved with high quality and nanometer thickness control by area-selective atomic layer deposition (AS-ALD). However, the current range of materials demonstrated deposited by AS-ALD is limited, and no processes for molybdenum oxide have been available so far. In this work, the authors explore the properties of a new ALD precursor, MoCl₄O, for deposition of molybdenum oxides by ALD. MoCl₄O is administered at room temperature during deposition, making it readily available for use. When reacted with a combination of water and ozone, it leads to an AS-ALD process for deposition of MoO_x—the first reported. The process is perfectly selective for growth on glass as compared to Si(100) substrates for deposition temperatures between 200 and 300 °C, with a growth rate of 0.72 Å/cycle at 300 °C. The process is attempted on a range of substrates proving good growth on soda-lime glass and LiF and no growth on Si(100), silica, Na₂CO₃, CaCO₃, Li₃PO₃, or Li₂SiO₃. The findings of this study indicate an activated process by diffusion of sodium or lithium through the film during growth. The obtained films have further been characterized by x-ray photoelectron spectroscopy, scanning electron microscopy, x-ray diffraction, and atomic force microscopy, revealing films with an RSM roughness of 23 nm with the presence of crystalline MoO₂ (C P/m) when deposited at 300 °C and crystalline Mo₉O₂₆ when deposited at 250 °C. The rough MoO_x thin films may be applicable for electrocatalysis, gas sensors, or lithium-ion batteries. The findings of this study enable AS-ALD synthesis of molybdenum oxide with excellent selectivity not dependent on intermittent etching cycles during growth.

中文翻译：

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氧化钼的区域选择性原子层沉积

需要薄膜的区域选择性的自下而上的合成路线来克服光刻中的电流限制，并且可以通过区域选择性原子层沉积（AS-ALD）通过高质量和纳米厚度控制来实现这种生长。但是，目前由AS-ALD证明的材料范围是有限的，到目前为止，尚无可用的氧化钼工艺。在这项工作中，作者探索了一种新的ALD前驱体MoCl ₄ O的性质，该前驱体用于通过ALD沉积钼氧化物。MoCl ₄ O在沉积过程中在室温下施用，使其易于使用。当与水和臭氧的混合物反应时，将导致AS-ALD工艺沉积MoO _x-第一个报告。与Si（100）基板相比，该工艺对于200至300°C的沉积温度具有完美的选择性，在300°C时的生长速率为0.72Å/循环。已尝试在证明在钠钙玻璃和LiF上生长良好且在Si（100），二氧化硅，Na ₂ CO ₃，CaCO ₃，Li ₃ PO ₃或Li ₂ SiO ₃上无生长的一系列基材上进行该工艺。这项研究的结果表明了激活生长过程中钠或锂通过薄膜扩散的过程。所获得的膜进一步通过X射线光电子能谱，扫描电子显微镜，X射线衍射和原子力显微镜表征，显示出当存在结晶MoO ₂（CP / m）时，RSM粗糙度为23nm的膜。在300°C时沉积，在250°C时沉积结晶Mo ₉ O ₂₆。粗糙的MoO _x薄膜可能适用于电催化，气体传感器或锂离子电池。这项研究的发现使AS-ALD氧化钼具有出色的选择性，而不受生长过程中间歇刻蚀周期的影响。