American Institute of Physics, Applied Physics Letters, 10(102), p. 104101
DOI: 10.1063/1.4792238
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The physics for integration of piezoelectric aluminum nitride (AlN) films with underlying insulating ultrananocrystalline diamond (UNCD), and electrically conductive grain boundary nitrogen-incorporated UNCD (N-UNCD) and boron-doped UNCD (B-UNCD) layers, as membranes for microelectromechanical system implantable drug delivery devices, has been investigated. AlN films deposited on platinum layers on as grown UNCD or N-UNCD layer (5–10 nm rms roughness) required thickness of ∼400 nm to induce (002) AlN orientation with piezoelectric d33 coefficient ∼1.91 pm/V at ∼10 V. Chemical mechanical polished B-UNCD films (0.2 nm rms roughness) substrates enabled (002) AlN film 200 nm thick, yielding d33 = 5.3 pm/V.