Charge storage unit and image sensor pixel circuit

Abstract

The invention provides a charge storage unit, comprising an input end and an output end. The charge storage unit comprises an exposure control transistor, an output transistor and a phase-change resistor, wherein the drain/source electrode of the exposure control transistor is the input end of the charge storage unit, and the drain/source electrode is connected to the first end of the phase-change resistor; the second end of the phase-change circuit is grounded; the drain/source electrode of the output transistor is connected to a co-connecting end of the drain/source electrode of the exposure control transistor with the cathode of a photodiode, the drain/source electrode is the output end of the charge storage unit, and the grid electrode is connected to an output control signal. The charge storage unit has the advantage that a phase-change resistor can be switched between an amorphous state and a crystal state, therefore, optical signals can be stored and voltage signals can be read through externally supplied driving current at last; furthermore, the state of phase-change material is not changed along external temperature or irradiation, and the phase-change material itself has the advantages of no volatility, low energy consumption and rapid reading and writing speed.

Description

technical field [0001] The present invention relates to the field of semiconductor technology, in particular to a charge storage unit and an image sensor pixel circuit. Background technique [0002] A CMOS image sensor is a semiconductor device manufactured using a CMOS manufacturing process that converts an image's optical signal into an electrical signal for transmission and processing. A CMOS image sensor generally consists of a photosensitive area and a signal processing circuit. At present, the common CMOS image sensor is the active pixel image sensor (APS), which is divided into two categories: three-tube image sensor (3T) and four-tube image sensor (4T). [0003] For the traditional 3T pixel circuit, in order to improve the dynamic range of the sensor, a mode of two long and short exposure times is adopted to collect dark light signals and bright light signals respectively, and finally a larger dynamic range is obtained through back-end signal processing. [0004] a...

AI Technical Summary

Problems solved by technology

but with figure 1 The structure shown will have the problem of charge leakage in the capacitor C, and the image cannot be saved for a long time. At the same time, it will be more sensitive to external interference, especially in the case of irradiation, the data is prone to errors

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