In-Situ Heat Treatment Study on the Nanocrystalline Cr2O3 Film Using an Environmental Scanning Electron Microscope

In this work, the surface morphology changes of nanocrystalline Cr2O3 film deposited on Si wafer during the heating process were observed in-situ by means of an environmental scanning electron microscope (ESEM). The Cr2O3 film cracked at high temperature due to the cause of thermal stress; the corresponding crack area percentages on the film surface were real-time evaluated using image analysis software (SISC IAS V8.0) based on the principle of gray value analysis. In the meantime, the effects of the heating temperature on the crack area percentage, phase constituents, and grain size of the Cr2O3 film were also studied in detail. The results showed that the percentage of crack area on film surface first increased with the heating temperature rise, and reached the maximum value at around 980 °C, and then gradually declined again. The above trend is closely related to the changes of thermal stress and grain growth in film. In addition, the heat treatment also had a strong influence on the grain size of the Cr2O3 film