Dark current reduction in stacked-type CMOS-APS for charged particle imaging

A stacked CMOS-active pixel sensor (APS) with a newly devised pixel structure for charged particle detection has been developed. At low operation temperatures (<200 K), the dark current of the CMOS-APS is determined by the hot carrier effect. A twin well CMOS pixel with a p-MOS readout and n-MOS reset circuit achieves low leakage current as low as 5×10^-8 V/s at the pixel electrode under liquid nitrogen temperature of 77 K. The total read noise floor of 0.1 mV_rms at the pixel electrode was obtained by nondestructive readout correlated double sampling (CDS) with the CDS interval of 21 s.