54results about How to "Increase full well capacity" patented technology

The invention relates to a complementary metal oxide semiconductor (CMOS) solid image sensor, and particularly relates to a photodiode and a method for improving the full-trap capacity and the quantum efficiency of an image sensor. In order to ensure that the extended full-trap capacity can be fully used up so that the extension is not based on wasting the streaking performance of images, and fundamentally improve key performance indexes of pixel units, such as dynamic range, signal to noise ratio, and sensitivity. In order to achieve the objective the invention adopts the following technicalscheme: an N buried layer with a shallower depth is injected to a P type epitaxial layer, a high-concentration P+-doped clamping layer is arranged on the N buried layer, a second N buried layer is arranged under the N buried layer, and a longitudinal P insertion layer structure is formed from the interface of the second N buried layer and the P type epitaxial layer to the inner part of the N buried layer. The photodiode and the method provided by the invention is mainly applied to the design and manufacture of the image sensor.

An image sensor and a forming method thereof are provided. The forming method comprises: providing a semiconductor substrate having a front surface and a back surface; performing first ion implantation on the semiconductor substrate from the front surface of the semiconductor substrate to form a front photodiode doped region; performing second ion implantation on the semiconductor substrate from the back surface of the semiconductor substrate to form a back photodiode doped region, wherein the front photodiode doped region and the back photodiode doped regions communicate with each other. Theforming method can improve the sensitivity of the image sensor.

The invention discloses an image sensor and a forming method thereof. The method includes steps of providing a semiconductor substrate, wherein the semiconductor substrate comprises a front face and aback face; etching the semiconductor substrate from the front face of the semiconductor substrate to form a front groove, filling a medium material in the front groove; etching the semiconductor substrate from the back face of the semiconductor substrate to form a back groove, wherein the back groove is correspondingly connected with the front groove; the semiconductor substrate between the connected front groove and the back groove is used for forming a photodiode; filling the medium material in the back channel. The scheme can effectively reduce the electricity crosstalk, improve the thickness of the photodiode, and further improve the full trap capacity.

The invention provides a method for forming an image sensor, comprising the following steps: providing a photodiode region; performing a first doping on the photodiode region by a first ion implantation process to form a buried layer; performing a second doping opposite to the first doping on a central region of the buried layer by a second ion implantation process, or performing the third dopinghaving the same type as the first doping on an edge region of the buried layer by a third ion implantation process. The technical proposal provided by the invention can effectively improve the gradient of the electric potential change in the buried layer edge region, so that the electric potential in the region rapidly changes from low to high, thereby improving the photodiode storage capacity ofphotoelectrons and effectively improving the full well capacity. In addition, using the opposite type of second doping can also effectively prevent the occurrence of image smearing in the center region.

The embodiment of the invention discloses a fingerprint recognition device and electronic equipment. The performance of the fingerprint recognition device can be improved. The fingerprint recognitiondevice is suitable for being arranged below a display screen to realize optical fingerprint recognition under the screen, the fingerprint recognition device comprises a plurality of fingerprint recognition units, and each fingerprint recognition unit comprises a micro lens; at least two light blocking layers, wherein each light blocking layer is provided with a light through hole to form two lightguide channels in different directions; the two pixel units are respectively positioned at the bottoms of the two light guide channels; wherein after fingerprint optical signals returned from a finger above the display screen are converged through the micro lens, two target fingerprint optical signals in different directions are transmitted to the two pixel units through the two light guide channels respectively. A plurality of groups of two pixel units in the fingerprint recognition device receive fingerprint optical signals in two different directions and convert the fingerprint optical signals into two fingerprint images, the two fingerprint images are moved and reconstructed into a reconstructed image, and the reconstructed image is used for fingerprint recognition.

The present disclosure provides CMOS image sensors and fabrication methods thereof. An exemplary fabrication process of a CMOS image sensor includes providing a substrate having a first region and a second region connecting with the first region at a first end of the first region: forming a transfer transistor on surface of the substrate in the second region; forming a first implanting region in the substrate in the first region using a first mask; forming a second implanting region in the first implanting region by, the first implanting region being separated into a third implanting region on the second implanting region and a fourth implanting region under the second implanting region; forming a fifth region in the second region at the first end using a second mask, connecting the third implanting region with the fourth implanting region.

The invention relates to an analog integrated circuit design, and aims to realize large full well and low electric leakage and improve the signal-to-noise ratio and the dynamic range of an image. Therefore, according to the technical scheme adopted by the invention, a PSD type transmission gate image sensor for reducing the feedforward effect comprises a photosensitive region PD, a transmission gate TG for controlling charge transfer from the PD to a storage node FD and a reset tube RST; when light irradiates a semiconductor, a part of light is absorbed by the semiconductor, when the absorbed energy is higher than the width of a silicon forbidden band, and an electron hole pair is generated; under the action of a built-in electric field, photo-induced electrons are collected by a depletion region in the PD; during reading, the TG is turned on, the TG under-gate channel is in a conducting state, photo-generated charges in the PD are transferred into the storage node FD, heavily-doped P-type doping is carried out on the transmission gate TG, low channel closing potential is obtained, and the barrier height of the PD and the channel is increased. The method is mainly applied to the design and manufacturing occasion of the CMOS image sensor.

The invention provides a preparation method of photodiodes, a photodiode and a CMOS image sensor. The preparation method includes: forming a shielding layer on a substrate, wherein the substrate has afirst doping type, and a preset position is arranged on the substrate, and the first doping type and the second doping type are different; processing the shielding layer to enable the thickness of the shielding layer above the preset position to be smaller than the thickness of the shielding layer above the non-preset position; performing ion implantation on the substrate, so that the implanted ions are formed into a curved surface having a second doping type to increase a contact area of the substrate and the region; and removing the shielding layer to obtain a photodiode. The preparation method of photodiodes increases the contact area of the substrate having a first doping type with a region having a second doping type, and increases the full well capacity.

The invention discloses a 4T pixel structure based on a semi-floating gate. The 4T pixel structure comprises a semi-floating gate device MSFG, three switching tubes and a capacitor, wherein the semi-floating gate device is used for collecting signal charges; the capacitor is similar to a photoelectric conversion region in a traditional 4T pixel, can be a capacitor of any type, is determined according to specific design and is used for converting a current signal output by the semi-floating gate device into a voltage signal; the three switch tubes can be switch tubes of any type, are determinedaccording to specific design, and are respectively used as a source follower MSF, a reset tube MRST and a selection tube MSEL; the source follower is used for signal amplification, and the reset tubeis used for resetting signals in the capacitor; and the selection tube is used for controlling the output of a pixel array row signal through a time sequence; The structure solves a problem of voltage distribution in a traditional 4T pixel photoelectric detection region and a photoelectric conversion region, and compared with a 1T pixel structure based on a semi-floating gate device, the pixel design with high full well capacity, large output swing and low noise can be realized.

The invention provides a CMOS image sensor and a manufacturing method. The CMOS image sensor comprises a P-type substrate, a P-type epitaxial layer and a plurality of pixel units, wherein the P-type epitaxial layer is formed on the P-type substrate, an N-type buried layer, a P-type clamping layer, the P-type buried layer and the P-type epitaxial layer form a clamping photodiode, the N-type buried layer, the P-type clamping layer and the P-type buried layer are all formed in the P-type epitaxial layer, the P-type clamping layer is formed above the N-type buried layer, the P-type buried layer is embedded into the N-type buried layer, the P-type buried layer comprises at least two P-type sub-buried layers, and the at least two P-type sub-buried layers are distributed in the depth direction of the P-type epitaxial layer. By using the P-type buried layer formed in the N-type buried layer, the width of a depletion region of the clamping photodiode is expanded, the PN junction capacitance is increased, and the quantum efficiency and the full well capacity of the pixel unit are improved, so that the sensitivity and the imaging performance of a pixel unit are improved, the N-type buried layer is easier to deplete before exposure, and the reset noise is reduced.

The invention relates to an image sensor and a manufacturing method thereof. The image sensor comprises a semiconductor substrate, an epitaxial layer located on the surface of the semiconductor substrate, a photosensitive element, wherein the photosensitive element comprises a first photosensitive element positioned in the semiconductor substrate and a second photosensitive element positioned in the epitaxial layer; and the second photosensitive element extends to the first photosensitive element. According to the image sensor, the epitaxial layer is grown on the semiconductor substrate, and the first photosensitive element and the second photosensitive element are formed on the semiconductor substrate and the epitaxial layer respectively, so that the process limitation caused by single manufacturing of the light sensing elements is avoided, and the longitudinal size of the light sensing elements is increased, the full-well capacity of each pixel unit is improved; and in addition, thetransistors of the pixel units of the image sensor are formed on the epitaxial layer, so that the transverse size of the photosensitive elements is enlarged, and the full-well capacity of each pixel unit is improved.

The embodiment of the invention relates to an image sensor and electronic equipment. The image sensor includes: a plurality of pixel unit groups, at least one pixel unit group comprises a color filterarray, wherein the color filter array comprises M first type filters, N second type filters and a light blocking area, the light blocking area comprises N light blocking sub-areas, and each light blocking sub-area is adjacent to the N second type filters; a pixel unit array positioned below the color filter array; wherein the pixel unit array comprises M first pixels and N second pixels, whereinthe M first pixels are in one-to-one correspondence with the M first type filters respectively, the N second pixels are in one-to-one correspondence with the N second type filters and the N light blocking sub-areas respectively, the area of the second pixels is larger than that of the first pixels, and M and N are integers larger than 0. According to the image sensor and the electronic equipment,the dynamic range of the image sensor is enlarged.

The invention discloses a shared pixel structure applied to automatic focusing and an image sensing device, and the structure comprises a first photodiode, a second photodiode, a first transmission transistor, a second transmission transistor, a floating diffusion point, a reset transistor, a source electrode following transistor, and a selection transistor. The first photodiode and the second photodiode are arranged at an interval, a connecting part is arranged between the first photodiode and the second photodiode, the shared pixel structure further comprises a control part, and the control part is used for controlling the connecting part to connect or disconnect the first photodiode and the second photodiode. According to the shared pixel structure and the image sensing device, the connecting part is arranged between the first photodiode and the second photodiode, so that the first photodiode and the second photodiode are connected or disconnected; the connecting part connecting the first photodiode and the second photodiode can increase the area of the whole photoelectric induction, so that the full well capacity is increased.