Piezoelectric films of AlN grown by reactive high-frequency magnetron sputtering

Abstract

For the manufacture of electronic devices, layered structures based on substances characterized by a complex of unique properties are promising. These substances include AlN, which has the property of field emission, is a piezoelectric and wide-gap semiconductor material and has high hardness, thermal conductivity, sound speed, stability at high temperatures. To create microwave acoustoelectronic devices, AlN is promising as a piezoelectric material with a strong piezoelectric effect. The main factor determining the achievement and reproducibility of the necessary physicochemical properties of AlN films, in particular, piezoelectric ones, is the ordered structure of the film. To solve the problem of producing films with an ordered atomic structure, sputtering methods are promising, in particular, magnetron sputtering, the application of which has no restrictions on the synthesis temperature and requirements for the substrate material. The disadvantage of growing films by magnetron sputtering is the production of multiphase material, which requires careful refinement of the synthesis conditions and control of the properties of the resulting substances. The method of reactive RF magnetron sputtering on substrates of amorphous and crystalline materials grown AlN films with a thickness of 10 nm to 10 μm. It was established that AlN films consist of X-ray-amorphous and axially textured <0001> crystalline phases. Using electron microscopy, X-ray diffractometry, energy dispersive spectroscopy, and Raman spectroscopy, we studied the influence of synthesis conditions on the composition and structure of AlN films. The Raman spectra of light of AlN films with different contents and structure of the crystalline phase are shown. The piezoelectric efficiency of the films was determined on the models of delay lines on surface acoustic waves. Understanding the features of crystallization and phase transformations during film growth by spraying methods helps to create layered structures with controlled values of functional properties and operational characteristics. The ability to control the piezoelectric efficiency of AlN films by Raman spectra is shown.