Evaluating fracture properties and interfacial strengths of silicon oxycarbide thin-films: XFEM simulations and experimental validation

Silicon oxycarbide (SiCO) thin films with unique nano-domain structure show various functional properties and high-temperature stability, and the mechanical property at the interface between SiCO and substrate is one of the critical issues for enhancing reliabilities of microelectronic thin-film devices. In this work, the fracture properties and interfacial strengths of SiCO thin films are investigated by experiments and extended finite element (XFEM) method. The elastic and plastic properties of the SiCO/substrate interfaces are obtained by fitting the XFEM calculated P-h curves with those from nano-indentation experiments, fracture toughnesses and energy release rates are obtained to improve the description of interfacial crack nucleation and propagation. Then the properties are used as the inputting parameters of XFEM model for scratch simulations, and the critical loads for evaluating interfacial strength are achieved. The calculated critical loads are comparable to the results of experimental scratch, and the influences of layer thickness on interfacial strength of SiCO thin-film are nicely predicted.