High Velocity Diamond Disk Resonator

The high fracture strength of polydiamond has enableda 167-MHz polydiamond disk resonator with a self-aligned polysilicon stem anchor to attain a velocity of 83 m/s, which is 56 times larger than the typical ~1.5 m/s [1] velocity employed by MEMS based sensors, such as gyroscopes. The key to this performance is the use of hot-filament chemical vapor deposited (HFCVD) diamond structural material with a fracture strength from 50-120 GPa [2] many times larger than the ~2.6 GPa average of polysilicon [3]. The resonator design herein further concentrates energy in the diamond resonator structure while removing it from the polysilicon stem. This not only suppresses energy loss to the substrate to permit a Q of 82,358 but also confines the high peak stress of 7.5 GPa (that would break polysilicon) to the diamond structure while lowering stress in the polysilicon stem to an acceptable 1.5 GPa. Velocities as high as demonstrated here should significantly improve the scale factors of MEMS-based sensors and the phase noise of MEMS-based oscillators alike.