WORKSHOP PAPER
A 1Mjot 1040fps 0.22e-rms Stacked BSI Quanta Image Sensor with Cluster-Parallel Readout
Abstract
A 1Mjot single-bit quanta image sensor (QIS) implemented in a stacked backside-illuminated (BSI) process is presented. This is the first work to report a megapixel photon-counting CMOS-type image sensor to the best of our knowledge. A QIS with 1.1µm pitch tapered-pump-gate jots is implemented with cluster-parallel readout, where each cluster of jots is associated with its own dedicated readout electronics stacked under the cluster. Power dissipation is reduced with this cluster readout because of the reduced column bus parasitic capacitance, which is important for the development of 1Gjot arrays. The QIS functions at 1040fps with binary readout and dissipates only 17.6mW, including I/O pads. The readout signal chain uses a fully differential charge-transfer amplifier (CTA) gain stage before a 1b-ADC to achieve an energy/bit FOM of 16.1pJ/b and 6.9pJ/b for the whole sensor and gain stage+ADC, respectively. Analog outputs with on-chip gain are implemented for pixel characterization purposes.Keywords
Quanta Image Sensor, Photon-Counting, Stacked BSI Process,References
1) E.R. Fossum, "What to do with sub-diffraction limit (SDL) pixels? - a proposal for a gigapixel digital film sensor (DFS)", IEEE Workshop on CCDs and Adv. Image Sensors, Karuizawa, (Japan, June 2005)., 2005
2) E.R. Fossum, et al., "The quanta image sensor: every photon counts", MDPI Sensors, 16(8), p. 1260, 2016. https://doi.org/10.3390/s16081260
3) J. Ma and E. R. Fossum, "Quanta image sensor jot with sub 0.3e- r.m.s. read noise and photon counting capability", IEEE Electron Device Letters, 36(9), 926-928, Sep. 2015. https://doi.org/10.1109/led.2015.2456067
4) S. Masoodian, et al., "A 2.5pJ/b binary image sensor as a pathfinder for quanta image sensors", IEEE Trans. Electron Devices, 63(1), 100-105, Jan. 2016. https://doi.org/10.1109/ted.2015.2457418
5) S. H. Chan, et al., "Images from bits: non-iterative image reconstruction for quanta image sensors", MDPI Sensors, 16(11), 2016. https://doi.org/10.3390/s16111961