Klement Philip, Anders Daniel, Gümbel Lukas, Bastianello Michele, Michel Fabian, Schörmann Jörg, Elm Matthias T, Heiliger Christian, Chatterjee Sangam
Institute of Experimental Physics I and Center for Materials Research (ZfM/LaMa), Justus Liebig University Giessen, Heinrich-Buff-Ring 16, Giessen D-35392, Germany.
Institute of Physical Chemistry, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, Giessen D-35392, Germany.
ACS Appl Mater Interfaces. 2021 Apr 28;13(16):19398-19405. doi: 10.1021/acsami.0c22121. Epub 2021 Apr 15.
Area-selective atomic layer deposition is a key technology for modern microelectronics as it eliminates alignment errors inherent to conventional approaches by enabling material deposition only in specific areas. Typically, the selectivity originates from surface modifications of the substrate that allow or block precursor adsorption. The control of the deposition process currently remains a major challenge as the selectivity of the no-growth areas is lost quickly. Here, we show that surface modifications of the substrate strongly manipulate surface diffusion. The selective deposition of TiO on poly(methyl methacrylate) and SiO yields localized nanostructures with tailored aspect ratios. Controlling the surface diffusion allows tuning such nanostructures as it boosts the growth rate at the interface of the growth and no-growth areas. Kinetic Monte-Carlo calculations reveal that species move from high to low diffusion areas. Further, we identify the catalytic activity of TiCl during the formation of carboxylic acid on poly(methyl methacrylate) as the reaction mechanism responsible for the loss of selectivity and show that process optimization leads to higher selectivity. Our work enables the precise control of area-selective atomic layer deposition on the nanoscale and offers new strategies in area-selective deposition processes by exploiting surface diffusion effects.
区域选择性原子层沉积是现代微电子学的一项关键技术，因为它通过仅在特定区域实现材料沉积，消除了传统方法固有的对准误差。通常，选择性源于对衬底的表面改性，这种改性允许或阻止前驱体吸附。目前，沉积过程的控制仍然是一个重大挑战，因为无生长区域的选择性会很快丧失。在此，我们表明对衬底的表面改性会强烈影响表面扩散。在聚甲基丙烯酸甲酯和二氧化硅上选择性沉积二氧化钛会产生具有定制纵横比的局部纳米结构。控制表面扩散可以调节此类纳米结构，因为它提高了生长区域和无生长区域界面处的生长速率。动力学蒙特卡罗计算表明，物质从高扩散区域向低扩散区域移动。此外，我们确定了在聚甲基丙烯酸甲酯上形成羧酸过程中四氯化钛的催化活性是导致选择性丧失的反应机制，并表明工艺优化可提高选择性。我们的工作实现了在纳米尺度上对区域选择性原子层沉积的精确控制，并通过利用表面扩散效应为区域选择性沉积过程提供了新策略。
