Stress measurement for nonstoichiometric ceria films based on Raman spectroscopy

Stress as an important parameter of thin films can seriously affect on the properties, performance and long-term stability of the films. Here, we propose a semiquantitative method based on Raman spectroscopy for the stress measurement on nonstoichiometric ceria oxide films . The “chemical strain” of lattice caused by oxygen deficits was a main obstacle factor for the stress measurement of CeO 2−δ films, which was overcome through the calibration of lattice vibration peaks by the normalized intensity of Ce 3+ ions in Raman spectra . A compressive stress about −1.38 ∼ −1.50 GPa was obtained on an oxidated Ce film, which was verified by the substrate-curvature method. Based on the proposed method, Raman spectroscopy could be expanded to wider application fields as an in-situ stress measurement tool, such as in the fields of oxygen-ion-conducting solid electrolytes , oxidation film of alloys, microelectronics and MEMS devices, etc.