Combined assessment of piezoelectric A1N films using X-ray diffraction, infrared absorption and atomic force microscopy

摘要

In this work we present the comparative study of sputtered A1N films by X-ray diffraction (XRD), infrared absorption in the reflectance mode (R-IR), atomic force microscopy (AFM) and the measurement of their piezoelectric response. The aim of this comparison is to achieve a good understanding of the information provided by each technique to relate it with the piezoelectric behaviour of the films. A large set of A1N films with different characteristics has been evaluated. We have observed that films with perfect c-axis orientation, as measured by XRD, exhibit an excellent piezoelectric response. The presence of traces of non-0002 reflections in the XRD patterns of some films, indicative of the existence of tilted grains, is related to a significant reduction in their piezoelectric response. In such cases, R-IR and AFM measurements are significantly more sensitive for the detection of tilted grains than conventional XRD measurements.