CC BY 4.0Ding, AnliAnliDingKirste, LutzLutzKirsteLu, YuanYuanLuDriad, RachidRachidDriadKurz, NicolasNicolasKurzLebedev, VadimVadimLebedevChristoph, TimTimChristophFeil, Niclas M.Niclas M.FeilLozar, RogerRogerLozarMetzger, ThomasThomasMetzgerAmbacher, OliverOliverAmbacherZukauskaite, AgneAgneZukauskaite2022-03-0613.5.20202020https://publica.fraunhofer.de/handle/publica/26237310.24406/publica-r-26237310.1063/1.5129329Non-polar a-plane Al0.77Sc0.23N(1120)thin films were prepared by magnetron sputter epitaxy on r-plane Al2O3 (1102) substrates. Different substrate off-cut angles were compared, and the off-cut angle of 3 resulted in the best structural quality of the AlScN layer. Structural characterization by x-ray diffraction confirmed that single phase, wurtzite-type, a-plane AlScN (1120), surface acoustic wave resonators were fabricated with wavelengths l = 2-10 lm (central frequency up to 1.7 GHz) with two orthogonal in-plane propagation directions. A strong dependence of electromechanical coupling on the in-plane orientation was observed. Compared to conventional c-plane AlScN based resonators, an increase of 185-1000% in the effective electromechanical coupling was achieved with only a fractional decrease of <10.5% in series resonance frequency.en667621journal article