Design of MEMS electrometer for highly sensitive charge measurement

A new scheme of MEMS vibrating reed electrometer is proposed, which has eliminated bias current leakage of preamplifiers. Its principle stays largely the same to Gunn's largescale electrometer proposed in 1932, input Charge is shared between a variable capacitor formed by the vibrating reed and a fixed capacitor, charge is measured by detecting the AC image current caused by charge redistribution. Theoretical calculation showed a charge resolution of 286 electrons in 0.3 Hz bandwidth, showing some compromise between charge resolution and bias current leakage.