Button shear testing for adhesion measurements of 2D materials.

Area of Science:

• Materials Science
• Microelectronics Engineering
• Surface Science

Background:

• Two-dimensional (2D) materials offer significant potential for microelectronics.
• Weak adhesion due to chemical inertness hinders reliable integration of 2D materials into functional devices.
• Quantifying adhesion is essential for advancing 2D device integration.

Purpose of the Study:

• To introduce and validate button shear testing as a method for measuring 2D material adhesion.
• To assess the adhesion of graphene, hexagonal boron nitride (hBN), molybdenum disulfide, and tungsten diselenide on silicon dioxide and silicon nitride.
• To identify factors influencing the adhesion of 2D materials.

Main Methods:

• Development of a fabrication process for polymer buttons on 2D materials.
• Establishment of optimal button dimensions and shear testing speeds.
• Application of button shear testing to evaluate adhesion on different substrates.

Main Results:

• Button shear testing demonstrated as a reliable and repeatable adhesion quantification method.
• Low substrate roughness and oxygen plasma treatment enhance 2D material shear strength.
• Thermal annealing improves hBN adhesion on silicon dioxide, correlating with thermal interface resistance.

Conclusions:

• Button shear testing is a viable technique for assessing 2D material adhesion.
• Surface preparation methods significantly impact the adhesion of 2D materials.
• Understanding adhesion is key to unlocking the full potential of 2D materials in microelectronics.