Polycrystalline diamond RF MEMS resonator technology and characterization

Due to material limitations of polycrystalline silicon resonators, polycrystalline diamond has been explored as a new RF MEMS resonator material. This work presents the development of polycrystalline diamond micro and nano resonators with quality factor (Q) values as high as 116,000.; Polycrystalline diamond resonator structures were tested using electrostatic and piezoelectric actuation. Similar resonator structures were tested using both testing methods, and their performance showed a difference in resonant frequency of about 3%, while the measured Q values differed by approximately a factor of 10.; The resonant frequency shifts due to different testing temperatures was quantified by the temperature coefficient (TCf) value, which ranged from -1.59x10-5/°C to -2.56x10 -5/°C for the different polycrystalline diamond structures. The Q values were not limited by clamping losses, phonon-phonon interaction or thermoelastic dissipation and they were measured as a function of temperature. The results showed an apparent thermally activated relaxation process, with an activation energy of 1.9 eV responsible for limiting the highest achievable Q value in the tested polycrystalline diamond resonators.; The fabrication technology and the performance of polycrystalline diamond resonators with dimensions in the nano scale are also presented. Polycrystalline diamond resonator cantilevers and torsional resonators with dimensions in the nanometer range (as small as 100 nm) have been fabricated and tested. The performance of these structures shows resonant frequencies and Q values in the range of 23 KHz--805 KHz and 2,800--103,600 respectively.