Dynamic fracture of SiO2 films due to laser-induced confined micro-explosion at the Si/SiO2 interface: time-resolved imaging and finite-element simulation

Abstract

Laser induced fracture of brittle solid films can be employed in transfer of brittle functional materials in a solid phase. The fracture process is driven by the confined laser-matter interaction (micro-explosion) near the interface of the donor film with the carrier substrate, and it is often difficult to preserve the structural integrity of the ejected donor segment (flyer) due to various dynamic damage phenomena. In this work, we consider SiO2 films grown on a silicon substrate by PECVD as a model system for studying laser-induced fracture of brittle solid films. The phenomena of the SiO2 flyer ejection and fragmentation at higher energies are studied experimentally using time-resolved imaging after irradiation by 10 ps 355 nm laser pulses, and computationally using a multiphysics finite-element model of the process. The results suggest that an intact transfer requires the fracture phenomena to be limited to the crack propagation from the edges of the laser-induced interface cavity to the surface of the film, while the dynamic tensile failure and inelastic shock compression can be the main reasons for the flyer damage and fragmentation.