A c-axis orientated aluminium nitride (AlN) film on a 128 degrees Y-X lithium niobate (LiNbO3) surface acoustic wave (SAW) device which exhibit a large electromechanical coupling coefficient (k(2)) and a high SAW velocity property, is needed for future communication applications. In this study, a c-axis orientated (B, Al)N film (with 2.6 at.% boron) was deposited on a 128 degrees Y-X LiNbO3 substrate by a co-sputtering system to further boost SAW device properties. The XRD and TEM results show that the (B, Al) N films show highly aligned columns with the c-axis perpendicular to the substrate. The hardness and Young's modulus of (B, Al) N film on 128 degrees Y-X LiNbO3 substrates are at least 17% and 7% larger than AlN films, respectively. From the SAW device measurement, the operation frequency characteristic of (B, Al) N film on 128 degrees Y-X LiNbO3 is higher than pure AlN on it. The SAW velocity also increases as (B, Al) N film thickness increases (at fixed IDT wavelength). Furthermore, the k(2) of (B, Al) N on the IDT/128 degrees Y-X LiNbO3 SAW device shows a higher value than AlN on it. (C) 2010 Elsevier B.V. All rights reserved.