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.