AVS 46th International Symposium
    Thin Films Division Monday Sessions
       Session TF-MoP

Paper TF-MoP24
Synthesis of Highly Oriented Piezoelectric AlN Films by Reactive Sputter Deposition

Monday, October 25, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: F. Engelmark, Uppsala University, Sweden
Authors: F. Engelmark, Uppsala University, Sweden
G. Fuentes, Uppsala University, Sweden
I.V. Katardjiev, Uppsala University, Sweden
A. Harsta, Uppsala University, Sweden
U. Smith, Uppsala University, Sweden
S. Berg, Uppsala University, Sweden
Correspondent: Click to Email
Nucleation and growth of polycrystalline AlN films on thermal and CVD oxide have been studied during RF reactive sputter deposition. The influence of the growth conditions, namely deposition pressure, RF power, Ar/N@sub 2@ ratio, substrate temperature, on film properties has been systematically studied. The properties of interest are crystallinity, degree of orientation, crystallite size, surface roughness, stress, piezoelectric coupling, acoustic velocity and others. The films have been analyzed with RBS, ESCA, XRD, ellipsometry, SEM, AFM, stress measurements, etc. It is found that these properties are sensitive functions of all deposition parameters and that there exist optimal deposition conditions under which films of high quality are obtained. The films at optimal conditions were analyzed with the following results: FWHM XRD 0.216 deg, FWHM rocking curve 1.62 deg, crystallite size 38 nm, optical index 2.15, surface roughness 31 Angstroms, stress 400 MPa. Further, to study the electro-acoustic properties of the films surface acoustic wave (SAW) filters were fabricated operating at 534 MHz. The thin film structure consists of AlN/SiO@sub 2@/Si. The electrodes of the interdigital transducers were made of Al. Examination of the frequency response indicated an acoustic velocity of 4900 m/s and a moderate coupling coefficient.