Open AccessAnalytical Modeling and TCAD Simulation of a Quanta Image Sensor Jot Device With a JFET Source-Follower for Deep Sub-Electron Read Noise
Author(s) -
Jiaju Ma,
Eric R. Fossum
Publication year - 2016
Publication title -
ieee journal of the electron devices society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.69
H-Index - 31
ISSN - 2168-6734
DOI - 10.1109/jeds.2016.2618721
Subject(s) - components, circuits, devices and systems , engineered materials, dielectrics and plasmas
A novel quanta image sensor (QIS) jot device with a CMOS compatible junction-field effect transistor (JFET) source follower (SF) is introduced. 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. The fundamental working principles of this device are discussed, and important functionalities are analyzed with simulation and theory.