Fabrication of aluminium nitride diamond and gallium nitride diamond SAW devices

Surface acoustic wave (SAW) devices have been fabricated from thin films of gallium nitride and aluminium nitride deposited on a range of chemical vap our deposition (CVD) diamond substrates. The growth of aluminium nitride an d gallium nitride layers on diamond by chemical beam epitaxy (CBE) is repor ted for the first time. Triethyl gallium and ethyldimethylamine alane precu rsors were used in conjunction with nitrogen from an RF atom source to depo sit the gallium nitride and aluminium nitride layers at substrate temperatu res in the range 540 to 575 degrees C. These layers have been characterised by Raman spectroscopy and atomic force microscopy. The SAW structures were completed by the deposition of gold or aluminium interdigitated electrode structures on the as-deposited nitride surfaces. Preliminary testing indica tes that these devices operate as bandpass filters with characteristics con sistent with the propagation of acoustic waves at very high phase velocitie s within the nitride-diamond multilayer substrate. (C) 1999 Elsevier Scienc e S.A. All rights reserved.