A pixel structure, image sensor and terminal

Abstract

The embodiment of the present application discloses a pixel structure, an image sensor, and a terminal, including: at least one photoelectric conversion unit, at least one transfer transistor, and a readout circuit; the source of the transfer transistor is connected to the photoelectric conversion unit, and the drain of the transfer transistor is connected to the To the readout circuit, the gate of the transfer transistor is used to receive the transfer control signal; the drain and the gate are located at the first section of the pixel structure, and the source is located at the second section of the pixel structure; the photoelectric conversion unit is used to absorb specific wavelength The optical signal converts the absorbed optical signal into an electrical signal; among them, the optical signals of specific wavelengths that can be absorbed by the photoelectric conversion units with different photosensitive area sizes are different; the transmission transistor is used to transmit the electrical signal of the photoelectric conversion unit to the reader. out of the circuit. In this way, the size of the photoelectric conversion unit along the cross-sectional direction can be as close as possible to the cross-sectional size of the pixel structure, which enlarges the volume of the photoelectric conversion unit, thereby obtaining a larger full well capacity.

Description

technical field [0001] The present application relates to image technology, and in particular to a pixel structure, an image sensor and a terminal. Background technique [0002] Complementary Metal Oxide Semiconductor (CMOS) image sensors are widely used in photography and camera products because of their low manufacturing cost and low power consumption. For CMOS image sensors, higher sensitivity, shorter exposure time and The shrinking pixel size has become a development trend of CMOS image sensors. [0003] A CMOS transmission gate (Transmission Gate, TG) is a controllable switch circuit that can transmit both digital and analog signals. The CMOS transmission gate is composed of a PMOS and an NMOS transistor connected in parallel, which has a very low on-resistance (hundreds of ohms) and a high off-resistance (greater than 10^9 ohms). [0004] The maximum amount of charge that can be accumulated by the capacitance of the photosensitive element photodiode (Photo-Diode, PD...

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Problems solved by technology

[0004] The maximum amount of charge that can be accumulated by the capacitance of the photosensitive element photodiode (Photo-Diode, PD) in the pixel structure is called the full well capacity. In the existing pixel structure, the electrode of the TG needs to occupy the spatial position of the PD, so that the full well of the PD Capacities are limited, which limits the range of light-sensing pixels

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