Monocrystalline 4H Silicon Carbide-on-Insulator Substrates for Nav-Grade Planar BAW Gyroscopes

This paper reports on the unique merits of monocrystalline hexagonal silicon carbide-on-insulator (4H-SiCOI) substrates for the implementation of maximally-driven bulk acoustic wave (BAW) gyroscopes on a chip. The scaling of performance in planar silicon micromechanical gyroscopes over the past two decades has hovered above inertial-grade level. The material properties of monocrystalline hexagonal silicon carbide, an isoelastic high acoustic velocity semiconductor with ultra-low internal damping, are superbly amenable to mode-matched ultra-high-Q micromechanical resonant gyroscopes with low mechanical Brownian noise. The recent development of 40,..m-thick bond and etch-back SiCOI substrates and their nanoscale-precision DRIE may enable maximally-driven ultra-high-Q planar SiC BAW gyroscopes with navigation-grade performance on a chip.