Electro-Mechanical Properties of Molybdenum Thin Film on Polyethylene Terephthalate Subjected to Tensile Stress

Molybdenum chips are vital in manufacturing photovoltaic cells and electronics because they offer a combination of high reliability, corrosion resistance, and exceptional electrical conductivity. These qualities make them suitable for applications demanding these characteristics. This study delves into the behavior of thin molybdenum films deposited on plastic substrates under increasing stress. Films of 100 nm and 200 nm thicknesses were stretched, revealing intricate relationships between crack formation, film thickness, and electrical conductivity. Scanning electron microscopy captured the evolution of cracks, initially forming perpendicular to stress and later branching at roughly 30 degrees, hinting at anisotropic material behavior. Thicker films displayed lower crack density and less branching, highlighting their enhanced stress resistance. Further, secondary cracks short between the original cracks was developed. Percentage change of electrical resistance mirrored this trend, gradually increasing with strain before a sharp spike and eventual disconnection due to crack-induced conductivity loss. Thinner films succumbed to failure at lower strains. These findings offer valuable insights into the design and optimization of molybdenum-based microelectronic devices and sensors, paving the way for further quantitative analysis to fully elucidate the intricate mechanisms at play.