Piezoelectric coefficient of InN films prepared by radio-frequency sputtering

Abstract An interferometric method has been used to measure the piezoelectric coefficient d 33 in indium nitride films deposited by radio-frequency sputtering on borosilicate glass coated with gold. This low temperature growth technique has the advantage of being able to produce samples for piezoelectric measurements where the InN film is grown directly on an Au metal back contact, allowing the accurate measurement of the piezoelectric coefficient of the InN layer without any parasitic series resistance. The InN growth conditions are described, and both crystal and optical characterizations of the film are presented. The measured value of the coefficient was found to be 4.0 ± 0.1 pm V − 1 .