1.51-GHz nanocrystalline diamond micromechanical disk resonator with material-mismatched isolating support

Abstract

The first CVD nanocrystalline diamond micromechanical disk resonator with material-mismatched stem has been demonstrated at a record frequency of 1.51 GHz with an impressive Q of 11,555, which is more than 7X higher than demonstrated in a previous 1.14-GHz polysilicon disk resonator, and which achieves a frequency-Q product of 1.74/spl times/10/sup 13/ that now exceeds the 1/spl times/10/sup 13/ of some of the best quartz crystals. In addition, a 1.27-GHz version with a Q in the excess of 12,000 exhibits a measured motional resistance of only 100 k/spl Omega/ with a dc-bias voltage of 20 V, which is more than 34X lower than measured on a pure polysilicon counterpart at 1.14 GHz. At 498 MHz, Q's up to 55,300 in vacuum and 35,550 in air have been demonstrated, both of which set frequency-Q product records at 2.75/spl times/10/sup 13/ (vacuum) and 1.77/spl times/10/sup 13/ (air).