3D global pixel unit and preparation method thereof

Abstract

The invention provides a 3D global pixel unit and a preparation method thereof. The unit comprises a photosensitive area and a 10T signal storage and reading area which arranged in a vertical direction. A photoelectric diode and a signal storage and reading circuit are mutually connected through adoption of a mode that a first dielectric layer and a second dielectric layer are connected, and a first direct connection structure and a second direct connection structure are connected. A rest switch and switch tubes are stored on a first sampling capacitor and a second sampling capacitor according to a certain timing sequence of a first switch tube, a second switch tube, a third switch tube and a fourth switch tube. A signal voltage obtained in exposure time is stored in pixel units for a certain period of time and then the signal voltage is read. Therefore, global shutter exposure of the whole pixel unit array is realized. According to the unit and the method, the10T signal storage and reading area and the photoelectric diode can be vertically and mutually connected; the optical path between an environment and the photoelectric diode is improved; the optical isolation degree of the signal storage capacitor is improved; and the area of a chip occupied by the pixel units is reduced.

Description

technical field [0001] The invention relates to the technical field of semiconductor image sensing, in particular to a 3D global pixel unit and a preparation method thereof. Background technique [0002] Traditional global shutter pixel technology is mainly used in CCD image sensors. Due to the increasing popularity of CMOS image sensors, and because machine vision, film production, industrial, automotive, and scanning applications must capture fast-moving objects with high Traditional barriers associated with shutter pixel technology. With this effort, the provided global shutter pixel technology has smaller pixel size, larger fill factor, lower dark current, and lower noise, making CMOS image sensors the preferred choice for CCD sensors in more applications. Viable alternatives. [0003] In the global pixel unit of a conventional CMOS image sensor, the photosensitive diode and the signal storage and readout circuit unit devices are all made in the same plane. The stora...

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Problems solved by technology

Moreover, the photosensitive unit, the storage capacitor and the readout circuit tend to interfere with each other

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