Effect of dielectric polarization noise on ultra-low-noise readout circuits

摘要

Dielectric polarization noise, which can be predicted by the fluctuation-dissipation theorem, is generated in materials that have dielectric loss. The materials around the gate circuit of an FET may generate dielectric polarization noise because these materials have dielectric loss. We measured the noise of both these materials and the devices, and fabricated an ultra-low-noise readout circuit by removing as many high-noise materials as possible and replacing the high-noise devices with lower-noise devices. The main noise sources in the circuit were the p-n junctions of the photodiode and the Si JFET, the feedback capacitor, and the electrode that connects them. A readout-noise level of ten electrons was achieved at 77 K using a phtodiode with a capacitance below 1 pF.