Interfacial Strength of Thin Film Measurement by Laser-Spallation

Improving adhesion properties and strength of thin films used in wide range of important application is the key factor in successfully manufacturing micro-electro-mechanical devices, multilayer micro-electronic and optical devices. Mechanical performance and reliably of thin film on a substrate depends on strength of interfacial adhesion. Understanding the role of process parameters like deposition condition and design parameters such as substrate thickness and film thickness, on mechanical performance of the layer is essential in optimizing manufacturing. However, there are limited techniques for characterizing intrinsic interfacial strength of thin films. The use of laser-generated stress pulses has shown the ability to provide quantitative evaluation of the adhesion strength of thin films. In the current work, we use the laser-spallation approach for the investigation of the adhesion strength of thin tin oxide films to alumina substrates.