15 GHz SAW nano-transducers using ultrananocrystalline diamond/AlN thin films

This article reports on the realization of high frequency surface acoustic wave (SAW) resonator architectures on a bi-layer aluminium nitride (AlN) /ultrananocrystalline diamond (UNCD) structure using electron beam lithography (EBL) and lift-off processes. The UNCD layer was simply synthesized using microwave plasma enhanced vapour deposition (MWPECVD). An optimized EBL process was utilized to fabricate the inter-digital transducers (IDTs) with a finger resolution of 145 nm. The fabricated device exhibited an operating frequency of 15.4 GHz, insertion loss of ~40 dB and an acoustic velocity of 8816 m/s.