Fabrication and evaluation of silicon micromechanical resonator using neutral beam etching technology

We present the fabrication and evaluation of silicon micromechanical resonators fabricated by neutral beam etching (NBE) to obtain narrow capacitive gap size for small motional resistance and low insertion loss. The resonant frequency of the fabricated devices with a length of 500 μm, width of 440 μm and thickness of 5 μm is 9.66 MHz, and the average quality factor (Q) value is around 78,000. The devices fabricated by both deep reactive ion etching (DRIE) and NBE are evaluated and compared. The devices fabricated by NBE show that the motional resistances are reduced by almost 11 times from 645 kΩ to 59 kΩ and their output signals (insertion loss) are increased by approximately 15 dB in comparison with those fabricated by DRIE.