Q-Factor Enhancement of Micro Hemispherical Resonators via Optimization of Film Distribution

Abstract

Micro hemispherical resonator gyroscopes (mHRG) offer significant advantages such as high precision and good reliability in inertial measurement applications. Thin-film damping of the resonators is a key factor limiting the performance improvement of mHRG. In this paper, we present a 3D mask-based metallization process that achieves ultra-thin 7 nm metallization on resonators through precise thickness distribution control. This method comprehensively analyzes the film thickness distribution and the energy distribution of the resonator, and reduces the film damping by regulating the film thickness distribution on the inner surface of the resonator through a mask. Our results show that this method reduces the film thickness from 13 nm to 7 nm (46.5% reduction) while maintaining the electrical conductivity and improving the Q-factor by 8.4 percentage points. The measured highest Q-factor of the 7 nm thin-film micro hemispherical resonator is 4.19 million, with an average Q-loss rate of 32.2%. Experimental validation confirms that the 7 nm Pt film not only meets the low resistance ( $\le 500~\Omega $ ) requirement, but also reduces the energy dissipation of the resonator by minimizing thermoelastic damping and internal friction. This approach provides an efficient film thickness modulation strategy for mHRG. [2025-0079]