Understanding the mechanical behaviour of materials is crucial in microelectronic components, where the response to thermo-mechanical loading during qualification and/or in service is a critical consideration. This study investigates the mechanical performance of piezoelectric single crystals, essential for various microelectronic applications. Serving as substrates for precise frequency filters for the newest 5G mobile communication standards, these brittle materials demand careful consideration of crystal orientations and surface qualities to ensure optimal functionality while enduring various loading conditions.
A notable gap in knowledge exists regarding the mechanical properties of these materials, including strength, fracture resistance, and the development of surface damage during grinding and polishing processes.
Fracture experiments, conducted at various length scales and loading scenarios, revealed significant variations in strength depending on crystal orientation and surface finishing. The grinding and polishing direction, particularly in relation to cleavage planes, emerges as a key factor affecting their mechanical performance. This influence becomes evident in changes to fracture patterns and (sub-) surface damage as identified through fractography.
These findings provide valuable insights for guiding the fabrication of brittle single crystals with specific orientations, optimizing both structural and functional properties. Macroscopic and microscopic investigations collectively offer a comprehensive understanding of the mechanical behaviour of these key piezoelectric materials in the microelectronic industry.