Nanotechnology for SAW devices on AlN epilayers

Hexagonal aluminum nitride (AlN) has revealed as an excellent candidate to be used as substrate for surface acoustic wave (SAW) devices. Its high SAW propagation velocity, electromechanical coupling constant and an almost negligible temperature coefficient of delay (TCD) promise the fabrication of low-cost SAW devices operating in the microwave region of the spectrum, useful under harmful environment conditions of temperature and radiation. In this paper, a revision of the excellent SAW-related characteristics of AIN grown by molecular beam epitaxy on sapphire is presented. Several technological issues related to the fabrication of high frequency ( > 1 GHz) SAW devices in this semiconductor using an e-beam lithographic system are discussed. On the other hand, design issues like the effect introduced by the generation of bulk acoustic waves (BAW) will be analyzed using a novel method based on the inverse Fourier transform. These approaches will be presented both from theoretical and experimental perspectives. (C) 2002 Elsevier Science B.V. All rights reserved.