Phase noise and frequency stability of very-high frequency silicon nanowire nanomechanical resonators

We report measurements and analyses of noise characteristics of very-high frequency (VHF) silicon nanowire (SiNW) nanoelectromechanical systems (NEMS). VHF SiNW resonators vibrating at similar to 200MHz typically have displacement sensitivity of similar to 5fm/Hz(1/2) and force sensitivity of 50 similar to 250aN/Hz(1/2) , set by thermomechanical fluctuations. They have similar to 1nm critical amplitude and intrinsic dynamic range of 90 similar to 11 0dB. Amplifier noise and resistor thermal noise dominate the resonance detection, resulting in compromised displacement noise floor (typically >= 30fm/Hz1/2), dynamic range (reduced to 70 similar to 90dB), and phase noise ( :>= 20 similar to 300 degradation). We develop SiNW-NEMS-based phase-locking techniques to investigate the phase noise and frequency stability performance. Frequency stability of similar to 0. 1 ppm and resonant mass sensitivity of similar to 10zg (1zg=10(-21)g) have been achieved.