Polycrystalline AlN films with preferential orientation by plasma enhanced chemical vapor deposition

• Published in: Thin solid films 2008-06, Vol.516 (15), p.4868-4875
• Main Authors: Sánchez, G., Wu, A., Tristant, P., Tixier, C., Soulestin, B., Desmaison, J., Bologna Alles, A.
• Format: Article
• Language: English
• Subjects: Aluminum nitride; Bulk acoustic wave devices; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Fourier transform infrared spectroscopy; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Physics; Piezoelectric films; Plasma enhanced chemical vapor deposition; Structure and morphology; thickness; Surface acoustic wave devices; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Theory and models of film growth; Thin film structure and morphology; Thin films; X-ray diffraction
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2007.09.030

AlN thin films for acoustic wave devices were prepared by Microwave Plasma Enhanced Chemical Vapor Deposition under different process conditions, employing Si (100) and Pt (111)/SiO 2/Si (100) substrates. The films were characterized by X-ray diffraction, Fourier transform infrared transmission spectroscopy, atomic force microscopy, scanning electron microscopy, and transmission electron microscopy. The values of the distance between the plasma and the tri-methyl-aluminum precursor injector, the radiofrequency bias potential, and the substrate temperature were central in the development of polycrystalline films. The choice of the chamber total pressure during deposition allowed for the development of two different crystallographic orientations, i.e., or . The film microstructures exhibited in general a column-like growth with rounded tops, an average grain size of about 40 nm, and a surface roughness lower than 20 nm under the best conditions.