CN103929600B - The shared dot structure of high sensitivity cmos image sensor - Google Patents
The shared dot structure of high sensitivity cmos image sensor Download PDFInfo
- Publication number
- CN103929600B CN103929600B CN201410183461.7A CN201410183461A CN103929600B CN 103929600 B CN103929600 B CN 103929600B CN 201410183461 A CN201410183461 A CN 201410183461A CN 103929600 B CN103929600 B CN 103929600B
- Authority
- CN
- China
- Prior art keywords
- active area
- transistor
- shared
- image sensor
- cmos image
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Solid State Image Pick-Up Elements (AREA)
- Transforming Light Signals Into Electric Signals (AREA)
Abstract
The invention discloses a kind of shared dot structure of high sensitivity cmos image sensor, including the charge pass transistor and the first floating active area of multiple photodiodes and equal number, also include that a reset transistor, a source follow transistor, a row selecting transistor and the second floating active area, separated by a switching transistor between the first floating active area and the second floating active area.Source follows transistor detection second to float the electric potential signal of active area, the parasitic capacitance of the second floating active area does not change with shared pixel quantity, the opto-electronic conversion gain of shared pixel is effectively increased, the luminous sensitivity of the cmos image sensor using shared dot structure can be effectively improved.
Description
Technical field
A kind of a kind of the present invention relates to imageing sensor, more particularly to the shared pixel of high sensitivity cmos image sensor
Structure.
Background technology
Imageing sensor has been widely used in digital camera, cell phone, medical apparatus and instruments, automobile and other application
Occasion.The fast development of CMOS (CMOS complementary metal-oxide-semiconductor) image sensor technologies is particularly manufactured, people couple are made
The output image quality of imageing sensor has higher requirement.
Cmos image sensor of the prior art, especially with the cmos image sensor of small area pixel cell,
Shared dot structure is generally used, such as two pixels are shared, and four pixels are shared, or more pixels are shared.Using picture
The shared major reason of element, is to save transistor, to expand the area of photodiode, and then improves the photosensitive sensitive of pixel
Degree；But this mode for improving luminous sensitivity, but sacrifices the opto-electronic conversion gain of floating active area, because shared structure
In each pixel charge pass transistor with floating active area be connected, and then increased floating active area parasitism electricity
Hold, shared pixel quantity is more, the parasitic capacitance for floating active area is bigger, so opto-electronic conversion gain is lower；The light of pixel
Electric conversion gain is lower, and luminous sensitivity is lower, and this is just photosensitive sensitive to improve with using the method for expanding photo-diode area
The original intention of degree is disagreed.
Imageing sensor of the prior art, with four transistor of cmos image sensor, four pixel shared structures (4T4S)
As a example by, as shown in figure 1,101～104 are respectively the photodiode of four pixels, 105～108 are respectively correspondingly four photoelectricity
The charge pass transistor of diode, 109 is reset transistor, and 110 follow transistor for source, and 111 is row selecting transistor,
112 is row bit line, and FD is floating active area；Wherein FD capacitive parts, C1 are the grid source of FD and each charge transfer transistor gate
Overlap capacitance, grid source overlap capacitances of the C2 for FD and 109, C3 and C4 are respectively the grid leak and grid source overlap capacitance of FD and 110,
Cm4 is FD line metallic parasitic electric capacity, and 4Caa is FD active area body capacitances.
As shown in Figure 1, the total capacitance that can draw FD is：
CFD4=4C1+C2+C3+C4+Cm4+4Caa
Coefficient 4 in 4C1 and 4Caa in equation is equal with the pixel quantity in shared structure, and Cm4 is proportional to pixel
Quantity.Therefore the parasitic total capacitance that can calculate N number of pixel shared structure Zhong FD areas is:
CFDn=nC1+C2+C3+C4+Cmn+nCaa
N in above-mentioned equation is bigger, and the transistor that pixel is averagely saved is more, and then the photodiode expansion of pixel
Area is more, and pixel sensitivity will be higher；But, the n in equation is bigger, and floating active area total capacitance CFDn is higher, so as to
Opto-electronic conversion gain is reduced, the luminous sensitivity of pixel is lower, this is carried with the method using expansion photodiode area
The original intention of high luminous sensitivity is disagreed.
Content of the invention
It is an object of the invention to provide a kind of shared dot structure of high sensitivity cmos image sensor, by using opening
The floating active area method that transistor isolation goes out little parasitic capacitance is closed, and the opto-electronic conversion gain of pixel is made not by shared pixel count
Amount affects.
The purpose of the present invention is achieved through the following technical solutions：
The shared dot structure of high sensitivity cmos image sensor of the present invention, including multiple photodiodes and identical
The charge pass transistor of quantity and the first floating active area, also include a reset transistor, source follow transistor, one
Individual row selecting transistor and the second floating active area, pass through one between the first floating active area and the second floating active area
Switching transistor separates.
As seen from the above technical solution provided by the invention, the high sensitivity cmos image sensor that the present invention is provided
Shared dot structure, due to will be less with parasitic capacitance for larger for parasitic capacitance the first floating active area using switching transistor
Second floating active area separate, source follow transistor detection second float active area electric potential signal, second floating active area
Parasitic capacitance not with shared pixel quantity change, effectively increase the opto-electronic conversion gain of shared pixel, can effectively improve
Luminous sensitivity using the cmos image sensor of shared dot structure.
Description of the drawings
Fig. 1 shows for the circuit of four transistors, four pixel shared structures (4T4S) of the cmos image sensor of prior art
It is intended to.
Fig. 2 is the circuit diagram of four pixel shared structures of the cmos image sensor in the embodiment of the present invention.
Potential well schematic diagrams one of the Fig. 3 for the shared pixel in the embodiment of the present invention in photoelectricity transfer operation.
Potential well schematic diagrams two of the Fig. 4 for the shared pixel in the embodiment of the present invention in photoelectricity transfer operation.
Specific embodiment
The embodiment of the present invention will be described in further detail below.
The shared dot structure of high sensitivity cmos image sensor of the present invention, its preferably specific embodiment is：
Including the charge pass transistor and the first floating active area of multiple photodiodes and equal number, also include one
Individual reset transistor, a source follow transistor, a row selecting transistor and the second floating active area, first floating to have
Separated by a switching transistor between source region and the second floating active area.
The drain electrode of the switching transistor is connected with the described second floating active area, source electrode and described first floats active area
It is connected.
The source follows the grid of transistor to be connected with the described second floating active area, and the source follows transistor to be used for visiting
Survey the electric potential signal change of the second floating active area.
In the shared dot structure of high sensitivity cmos image sensor, the pixel quantity that shared pixel includes is more than
Or it is equal to two.
The change of quantity that the parasitic total capacitance of the second floating active area does not include with shared pixel and change.
When photo-electric charge transfer operation is carried out, the potential of the first floating active area is complete higher than the photodiode
Fully- depleted potential 0V～0.3V.
The first floating active area includes the active area of transistor source and drain active area or photodiode technique.
The photodiode includes Pin type photodiodes, part Pin types photodiode or polysilicon grid-type light
Electric diode.
The shared dot structure of high sensitivity cmos image sensor of the invention, due to using switching transistor by parasitism
The first larger floating active area of electric capacity the second floating active area less with parasitic capacitance separates, and source follows transistor to detect the
The electric potential signal of two floating active areas, the parasitic capacitance of the second floating active area do not change with shared pixel quantity, effectively improve
The opto-electronic conversion gain of shared pixel, can effectively improve the sensitive of cmos image sensor using shared dot structure
Degree.
Specific embodiment：
In an embodiment of the present invention, by taking four pixel shared structure of cmos image sensor as an example, adopt in this dot structure
With Pin type N-type photodiodes, the transistor in pixel adopts N-type transistor.
As shown in Fig. 2 including the electric charge in 201～204, four pixels of photodiode of four pixels in shared structure
Transmission transistor 205～208, reset transistor 209, source follow transistor 210, row selecting transistor 211, row bit line 212, open
Close transistor 213；The gate terminal of charge pass transistor 205～208 is respectively TX1, TX2, TX3 and TX4, reset transistor
209 and the gate terminal of row selecting transistor 211 be RX and SX, the gate terminal of switching transistor 213 is TX, and Vdd is supply voltage；
FD4 is the first floating active area, and FD is the second floating active area, and C1 is the overlap capacitance of FD and TX, and C2 is the overlapping of FD and RX
Electric capacity, C3 and C4 are respectively the drain electrode of FD and 210 and the overlap capacitance of source electrode, and Cm1 is FD metal capacitances, and Caa is FD active areas
Body capacitance.
From embodiment accompanying drawing 2, it can be found that the floating active areas of FD4 and FD two are separated by switching transistor 213, source with
With the potential change that 210 direct detection second of transistor floats active area FD, the parasitic capacitance expression of the second floating active area FD
For：
CFD=Cm1+Caa+C1+C2+C3+C4
Therefore, the CFD4 of traditional 4T4S structure of the CFD expression formulas in this enforcement row than illustrating in the introduction is few
3C1+3Caa, and the Cm4 that can be less than according to design experiences Cm1 in tradition 4T4S structures；CFD expression formulas from the present embodiment
In can draw：The value of FD parasitic capacitances CFD does not change with the change of shared pixel quantity, and CFD can be always maintained at not altogether
The minima for enjoying 4T dot structures is constant.The size of CFD values determines that the opto-electronic conversion gain C.G. of pixel, expression formula are:
C.G.=q/CFD
Q in expression formula is an electron charge 6.02E-19 coulomb.The luminous sensitivity of pixel is proportional to opto-electronic conversion
Gain C.G., therefore the pixel of present invention pixel shared structure, while expansion photodiode area advantage is remain, goes back
Remain the constant advantage of the opto-electronic conversion gain of pixel, and opto-electronic conversion yield value and unshared structure 4T dot structure
Opto-electronic conversion yield value is identical.So the method for the shared dot structure of the present invention solves the shared pixel opto-electronic conversion of tradition and increases
The shortcoming that benefit reduces, improves the luminous sensitivity of shared pixel.
The operation principle of specific embodiment is：
Realize that the method for work of present invention pixel there are two kinds, pixel operation as shown in Figure 3 and Figure 4 is shifted in photo-electric charge
Potential well schematic diagram during step.
Shown in Fig. 3,301～304 characterize the potential well of four photodiodes in shared pixel respectively, 305～308 points
Four charge pass transistors in shared pixel are not characterized, 309 is reset transistor, 313 is switching transistor, 314 tables
The potential well of the first floating active area FD4 is levied, 315 characterize the second potential well for floating active area FD, and 316 characterize supply voltage potential well；
TXn is 305～308 gate terminal, and wherein n is 1,2,3 and 4；TX and RX is respectively 313 and 309 gate terminal；CFD represents picture
The parasitic capacitance of the second floating active area of element.Potential well state shown in Fig. 3 is the operation that pixel operation is shifted in photo-electric charge
Process, wherein 305～308 and 313 dotted line below represent its gate terminal when being GND, i.e., when transistor is closed
Potential barrier schematic diagram.
Completely depleted potential of work potential VFD4 of the first floating active area FD4 shown in Fig. 3 higher than photodiode
The scope of Vpin is 0V～0.3V, and the technique of the first floating active area is using tradition CIS standard logic process.
Realize for second the operation potential well schematic diagram of present invention pixel structure charge transfer as shown in figure 4,401～404 points
The potential well of four photodiodes in shared pixel is not characterized, and 405～408 characterize four electricity in shared pixel respectively
Lotus transmission transistor, 409 is reset transistor, and 413 is switching transistor, and 414 characterize the first potential well for floating active area FD4,
415 characterize the second potential well for floating active area FD, and 416 characterize supply voltage potential well；TXn is 405～408 gate terminal, wherein n
For 1,2,3 and 4；TX and RX is respectively 413 and 409 gate terminal；CFD represents the parasitism electricity of the second floating active area of pixel
Hold.Potential well state shown in Fig. 4 is the operating process that pixel operation is shifted in photo-electric charge, below wherein 405～408 and 413
Dotted line represent its gate terminal be GND when, i.e., potential barrier schematic diagram when transistor is closed.
Completely depleted potential of work potential Vpin4 of the first floating active area FD4 shown in Fig. 4 higher than photodiode
The scope of Vpin is 0V～0.3V, and wherein, the technology type that FD4 active areas are adopted is identical with the technology type of photodiode,
And in charge transfer state, FD4 has been completely depleted pixel operation, its completely depleted potential is Vpin4.
The above, the only present invention preferably specific embodiment, but protection scope of the present invention is not limited thereto,
Any those familiar with the art in the technical scope of present disclosure, the change or replacement that can readily occur in,
Should all be included within the scope of the present invention.Therefore, protection scope of the present invention should be with the protection model of claims
Enclose and be defined.
Claims (8)
1. the shared dot structure of a kind of high sensitivity cmos image sensor, including multiple photodiodes and equal number
Charge pass transistor and the first floating active area, also include that a reset transistor, a source follow transistor, a row choosing
Select transistor and the second floating active area, it is characterised in that lead between the first floating active area and the second floating active area
Cross a switching transistor to separate.
2. the shared dot structure of high sensitivity cmos image sensor according to claim 1, it is characterised in that described
The drain electrode of switching transistor is connected with the described second floating active area, source electrode is connected with the described first floating active area.
3. the shared dot structure of high sensitivity cmos image sensor according to claim 2, it is characterised in that described
Source follows the grid of transistor to be connected with the described second floating active area, and the source follows transistor to float for detecting described second
The electric potential signal change of floating active area.
4. the shared dot structure of high sensitivity cmos image sensor according to claim 3, it is characterised in that the height
In the shared dot structure of sensitivity cmos image sensor, the pixel quantity that shared pixel includes is more than or equal to two.
5. the shared dot structure of high sensitivity cmos image sensor according to claim 4, it is characterised in that described
The change of quantity that the parasitic total capacitance of the second floating active area does not include with shared pixel and change.
6. the shared dot structure of high sensitivity cmos image sensor according to any one of claim 1 to 5, its feature
It is, when photo-electric charge transfer operation is carried out, the potential of the first floating active area is complete higher than the photodiode
Exhaust potential 0V～0.3V.
7. the shared dot structure of high sensitivity cmos image sensor according to claim 6, it is characterised in that described
First floating active area includes the active area of transistor source and drain active area or photodiode technique.
8. the shared dot structure of high sensitivity cmos image sensor according to claim 6, it is characterised in that described
Photodiode includes Pin type photodiodes, part Pin types photodiode or polysilicon grid-type photodiode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410183461.7A CN103929600B (en) | 2014-04-30 | 2014-04-30 | The shared dot structure of high sensitivity cmos image sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410183461.7A CN103929600B (en) | 2014-04-30 | 2014-04-30 | The shared dot structure of high sensitivity cmos image sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103929600A CN103929600A (en) | 2014-07-16 |
| CN103929600B true CN103929600B (en) | 2017-03-15 |
Family
ID=51147661
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410183461.7A Active CN103929600B (en) | 2014-04-30 | 2014-04-30 | The shared dot structure of high sensitivity cmos image sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103929600B (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10418407B2 (en) | 2015-11-06 | 2019-09-17 | Artilux, Inc. | High-speed light sensing apparatus III |
| JP6461429B2 (en) * | 2015-12-18 | 2019-01-30 | 広東欧珀移動通信有限公司 | Image sensor, control method, and electronic apparatus |
| TWI596946B (en) * | 2016-08-18 | 2017-08-21 | 友達光電股份有限公司 | Signal reading circuit |
| WO2018221074A1 (en) * | 2017-05-28 | 2018-12-06 | 国立大学法人東北大学 | Light-receiving device and method for reading signal of light-receiving device |
| US10510796B1 (en) * | 2018-06-14 | 2019-12-17 | Omnivision Technologies, Inc. | Small pixels having dual conversion gain providing high dynamic range |
| CN109148497B (en) * | 2018-07-19 | 2020-12-25 | 上海集成电路研发中心有限公司 | Global pixel structure for preventing parasitic light response and forming method |
| US11448830B2 (en) * | 2018-12-12 | 2022-09-20 | Artilux, Inc. | Photo-detecting apparatus with multi-reset mechanism |
| EP3754369A1 (en) | 2019-06-19 | 2020-12-23 | Artilux Inc. | Photo-detecting apparatus with current-reuse |
| KR20210099350A (en) * | 2020-02-04 | 2021-08-12 | 에스케이하이닉스 주식회사 | Image sensing device |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1764246A (en) * | 2004-10-19 | 2006-04-26 | 索尼株式会社 | Solid-state imaging device |
| CN1828919A (en) * | 2005-02-07 | 2006-09-06 | 三星电子株式会社 | CMOS sensor array with a shared structure |
| CN102394239A (en) * | 2011-11-24 | 2012-03-28 | 上海宏力半导体制造有限公司 | Image sensor of CMOS (Complementary Metal-Oxide-Semiconductor Transistor) |
| CN102413288A (en) * | 2011-11-02 | 2012-04-11 | 上海宏力半导体制造有限公司 | Transfer transistor structure for image sensor and image sensor |
| CN102856339A (en) * | 2012-09-24 | 2013-01-02 | 北京思比科微电子技术股份有限公司 | CMOS (complementary metal oxide semiconductor) image sensor column shared pixel unit and pixel array |
| CN203813866U (en) * | 2014-04-30 | 2014-09-03 | 北京思比科微电子技术股份有限公司 | High-sensitivity CMOS image sensor shared-type pixel structure |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5895525B2 (en) * | 2011-12-28 | 2016-03-30 | 株式会社ニコン | Image sensor |
-
2014
- 2014-04-30 CN CN201410183461.7A patent/CN103929600B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1764246A (en) * | 2004-10-19 | 2006-04-26 | 索尼株式会社 | Solid-state imaging device |
| CN1828919A (en) * | 2005-02-07 | 2006-09-06 | 三星电子株式会社 | CMOS sensor array with a shared structure |
| CN102413288A (en) * | 2011-11-02 | 2012-04-11 | 上海宏力半导体制造有限公司 | Transfer transistor structure for image sensor and image sensor |
| CN102394239A (en) * | 2011-11-24 | 2012-03-28 | 上海宏力半导体制造有限公司 | Image sensor of CMOS (Complementary Metal-Oxide-Semiconductor Transistor) |
| CN102856339A (en) * | 2012-09-24 | 2013-01-02 | 北京思比科微电子技术股份有限公司 | CMOS (complementary metal oxide semiconductor) image sensor column shared pixel unit and pixel array |
| CN203813866U (en) * | 2014-04-30 | 2014-09-03 | 北京思比科微电子技术股份有限公司 | High-sensitivity CMOS image sensor shared-type pixel structure |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103929600A (en) | 2014-07-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103929600B (en) | The shared dot structure of high sensitivity cmos image sensor | |
| KR100256835B1 (en) | Single split-gate mos transistor active pixel sensor cell with automatic blooming and wide dynamic range | |
| US20040218078A1 (en) | Complementary metal oxide semiconductor image sensor with multi-floating diffusion region | |
| CN103139499B (en) | There is imageing sensor active pixel and the imageing sensor of variable conversion gain | |
| US11342367B2 (en) | Photosensitive detector, imaging sensor chip formed using the photosentive detector, and detection method | |
| CN101556962B (en) | Image sensor with sensing transistor having two gates and method of operating the same | |
| CN101853867A (en) | Solid state image pickup device and manufacture method thereof and electronic equipment | |
| CN103152529A (en) | Pixel structure for improving charge transfer efficiency and reducing dark current and working method of pixel structure | |
| CN105227870B (en) | Larger Dynamic range line-log responds cmos image sensor | |
| CN104485342B (en) | Pixel structure of image sensor and operating method for pixel structure | |
| CN100565897C (en) | Use the cmos image sensor and the manufacture method thereof of surface field effect | |
| CN109728015A (en) | The imaging sensor of settling time with reduction | |
| CN204217043U (en) | Three dynamic range expanded transistor image sensor dot structures | |
| CN104010142B (en) | Active pixel and imaging sensor and its control sequential | |
| CN103139497B (en) | The active pixel and cmos image sensor of cmos image sensor | |
| CN103928485B (en) | A kind of radioscopic image sensor of high output amplitude | |
| CN203813866U (en) | High-sensitivity CMOS image sensor shared-type pixel structure | |
| CN204031312U (en) | The image sensor pixel of variable conversion gain | |
| KR100298199B1 (en) | A unit pixel of a CMOS image sensor having a PIN diode | |
| CN104754254B (en) | Imaging device and imaging system | |
| KR20090015651A (en) | Unit pixel improving image sensitivity and dynamic range | |
| CN204632761U (en) | Imageing sensor | |
| CN204069153U (en) | Active pixel structure and imageing sensor | |
| CN103915457A (en) | Silicon-based CMOS image sensor and method of the silicon-based CMOS image sensor for restraining photon-generated carrier surface trap recombination | |
| CN104022133B (en) | Active pixel with floating diffusing node provided with variable capacitance and image sensor |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |