Residual noise reduction in AlN resonators by prolonged RF excitation

Very low phase noise oscillators are highly desirable for military radar applications. In order to improve phase noise performance of micro-electro-mechanical-systems (MEMS) oscillators, it is essential to reduce the residual noise of the resonator, which serves as the frequency selective element. The oscillator closed loop phase noise is typically limited by the 1/f flicker noise intrinsic to the MEMS resonator acting as the frequency selective element. In this work, the ability to reduce the 1/f flicker noise and consequently the residual phase noise of 1GHz MEMS aluminum nitride (AlN) contour mode resonators (CMR) by prolonged exposure to RF power at resonant frequency is explored.