Open access IEEE Journal of the Electron Devices Society publishes a paper "Analytical Modeling and TCAD Simulation of a Quanta Image Sensor Jot Device With a JFET Source-Follower for Deep Sub-Electron Read Noise" by Jiaju Ma and Eric R. Fossum, Dartmouth College. From the abstract:
"The device is proposed to further reduce the read noise of QIS jots and ultimately realize a read noise of 0.15e-r.m.s. for accurate photoelectron counting. We take advantage of the small gate capacitance in a p-channel JFET SF to reduce the total capacitance of the floating diffusion, which yields a greatly improved conversion gain of 1.38 mV/e- in TCAD simulation compared to MOSFET SF with the same pitch size. Lower 1/ f noise is also anticipated yielding a low input-referred read noise. The device is designed in a 45 nm CMOS image sensor process."