Active pixel of cmos image sensor and cmos image sensor

Abstract

The invention discloses an active pixel of a complementary metal oxide semiconductor (CMOS) image sensor. The active pixel at least comprises a photosensitive component which is placed inside a semi-conductor substrate, a reset transistor and a source following transistor which are connected with the photosensitive component, a switch transistor, and a row positioning line. The pixel photosensitive component of the image sensor comprises two photosensitive regions, namely a low dose foreign ion injection region, and a high dose foreign ion injection region near the reset transistor. When in low illumination, photo-electricity charge generated in the photosensitive component is only collected in the high dose foreign ion injection region, grain of photo-electricity transition is high, and sensitivity of the sensor is high. When in high illumination, photo-electricity charge generated in the photosensitive component is collected in the whole photosensitive component. Therefore, the active pixel can effectively improve the luminous sensitivity of the image sensor in the low illumination, and the sensor collects more real object detail information when in the low illumination.

Description

technical field [0001] The invention relates to an image sensor, in particular to an active pixel of a CMOS image sensor and a CMOS image sensor. Background technique [0002] Image sensors have been widely used in digital cameras, mobile phones, medical devices, automobiles and other applications. In particular, the rapid development of CMOS (Complementary Metal Oxide Semiconductor) image sensor technology has made people have higher requirements for the output image quality of image sensors. [0003] In the prior art, a CMOS image sensor generally adopts a pixel structure with a linear photoelectric response function. Such as figure 1 As shown, the CMOS image sensor uses a three-transistor active pixel, which is also called a 3T active pixel in the art. The components of a 3T active pixel include: a photodiode 101, a reset transistor 102, a source follower transistor 103 and a switch transistor 104, and column bit line 105; One end VPD of photodiode 101 is connected wit...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide an active pixel of a CMOS image sensor and a CMOS image sensor, which can ensure the quality of the output image, thereby solving the problem that the linear sensor is difficult to collect physical information in a low-light environment

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