This paper presents the design and fabrication of a 500μm×200μm×0.070μm micro-cantilever as ultrasonic frequency generator. Actuation energy (up to 4.1V dc) after fixed intervals was necessary to produce stable oscillations. The device relies on the principle of electrostatic effect and the output in the form of low ultrasonic frequency signal is generated from the piezoelectric surface (ZnO) due to switching action. The dimensions of the proposed device are first optimized by modeling and the same design is then fabricated and characterized as high frequency signal generator. From the results, a huge difference between the simulated (22.67kHz) and experimental (30.76kHz) output signals has been found out. This may be caused due to a propagation delay and slow switching action in fabricated device. This work may be useful as an electrostatic micro-switch where low actuation dc voltage is needed to generate ultrasound signals.