In this paper, the frequency characteristics ofhigh overtone bulk acoustic modes, generated by interdigitaltransducers IDT’s on c-tilted ZnO/Si, are theoretically andexperimentally investigated. The origin and characteristics ofhigh overtone acoustic modes in ZnO piezoelectric layer onsilicon substrate are discussed and one port HBAR resonator,based on c-axis tilted ZnO/Si, is fabricated and tested bynetwork analyzer. The results achieved in this work are ofinterest in design and fabrication of radiofrequency sourcesand electronic timing devices based on thin film technology