The effects of low temperature and vacuum on the fracture behavior of organosilicate thin films
MetadataShow full item record
A novel load-displacement sensing instrument has been designed and fabricated to characterize the fracture properties of brittle thin films at low temperature (-30 °C) and pressure (1.6e-4 Pa). In this study, the instrument was used to investigate the effects of harsh environments on the fracture energies of organosilicate glass (OSG) and silicon carbonitride (SiCN) thin films under four-point bend loading. Experiment results showed that the energy release rates of film stacks are the highest when the environment contains a very low water molecule concentration. This condition can be achieved by purging the testing chamber with pure nitrogen or reducing the chamber pressure to less than 1 Pa. In contrast, cracks propagated readily along OSG/SiCN interfaces when experiments were performed submerged in de-ionized (DI) water. The effect of low temperature (-30 °C) on thin film fracture was also studied and the results demonstrated that there is no observed degradation of the OSG fracture properties. X-ray photoelectron spectroscopy (XPS) was used to identify the chemical composition of the fracture surfaces. Furthermore, a finite element model was used to investigate the effects on the stress intensity factors at the crack tip of a four-point bend sample when a compliant epoxy layer is present in the film stack.
Cite this work
Soheil Barakat (2011). The effects of low temperature and vacuum on the fracture behavior of organosilicate thin films. UWSpace. http://hdl.handle.net/10012/5919