Schätz Josef, Nayi Navin, Weber Jonas, Metzke Christoph, Lukas Sebastian, Walter Jürgen, Schaffus Tim, Streb Fabian, Reato Eros, Piacentini Agata, Grundmann Annika, Kalisch Holger, Heuken Michael, Vescan Andrei, Pindl Stephan, Lemme Max C
Infineon Technologies AG, Wernerwerkstraße 2, 93049, Regensburg, Germany.
Chair of Electronic Devices, RWTH Aachen University, Otto-Blumenthal-Str. 25, 52074, Aachen, Germany.
Nat Commun. 2024 Mar 18;15(1):2430. doi: 10.1038/s41467-024-46136-8.
Two-dimensional (2D) materials are considered for numerous applications in microelectronics, although several challenges remain when integrating them into functional devices. Weak adhesion is one of them, caused by their chemical inertness. Quantifying the adhesion of 2D materials on three-dimensional surfaces is, therefore, an essential step toward reliable 2D device integration. To this end, button shear testing is proposed and demonstrated as a method for evaluating the adhesion of 2D materials with the examples of graphene, hexagonal boron nitride (hBN), molybdenum disulfide, and tungsten diselenide on silicon dioxide and silicon nitride substrates. We propose a fabrication process flow for polymer buttons on the 2D materials and establish suitable button dimensions and testing shear speeds. We show with our quantitative data that low substrate roughness and oxygen plasma treatments on the substrates before 2D material transfer result in higher shear strengths. Thermal annealing increases the adhesion of hBN on silicon dioxide and correlates with the thermal interface resistance between these materials. This establishes button shear testing as a reliable and repeatable method for quantifying the adhesion of 2D materials.
二维（2D）材料在微电子领域有众多应用，不过将它们集成到功能器件中仍存在一些挑战。弱附着力就是其中之一，这是由其化学惰性导致的。因此，量化二维材料在三维表面上的附着力是实现可靠二维器件集成的关键一步。为此，本文提出并演示了纽扣剪切测试法，以石墨烯、六方氮化硼（hBN）、二硫化钼和二硒化钨为例，评估它们在二氧化硅和氮化硅衬底上的附着力。我们提出了一种在二维材料上制备聚合物纽扣的工艺流程，并确定了合适的纽扣尺寸和测试剪切速度。我们的定量数据表明，在转移二维材料之前，较低的衬底粗糙度以及对衬底进行氧等离子体处理会导致更高的剪切强度。热退火提高了hBN在二氧化硅上的附着力，并与这些材料之间的热界面电阻相关。这确立了纽扣剪切测试法作为一种可靠且可重复的量化二维材料附着力的方法。
