CN103208502A - Complementary Metal-Oxide-Semiconductor Transistor (CMOS) image sensor and production method thereof - Google Patents
Complementary Metal-Oxide-Semiconductor Transistor (CMOS) image sensor and production method thereof Download PDFInfo
- Publication number
- CN103208502A CN103208502A CN201310085156XA CN201310085156A CN103208502A CN 103208502 A CN103208502 A CN 103208502A CN 201310085156X A CN201310085156X A CN 201310085156XA CN 201310085156 A CN201310085156 A CN 201310085156A CN 103208502 A CN103208502 A CN 103208502A
- Authority
- CN
- China
- Prior art keywords
- photodiode
- area
- image sensor
- cmos image
- ion
- 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.)
- Pending
Links
Images
Landscapes
- Solid State Image Pick-Up Elements (AREA)
Abstract
A Complementary Metal-Oxide-Semiconductor Transistor (CMOS) image sensor comprises a photodiode, a shifting transistor, a reset transistor, a first floating node and a second floating node which are arranged in a semiconductor substrate and an isolation structure used for device electric isolation. The photodiode is provided with at least two zones, namely a first zone and a second zone, having different indium doping concentrations, and the indium doping concentration of the first zone located at the far end of the shifting transistor is smaller than that of the second zone located at the near end of the shifting transistor. At least two-time ion injection at different angles is adopted, and an internal electric field E pointing from the second zone to the first zone is formed in the photodiode through the shielding effect of ion injection, so that photoelectron transmission speed is improved, the number of photoelectrons detained in the photodiode is reduced, photoelectron collection efficiency of the photodiode is improved, and image delay or information losing is reduced.
Description
Technical field
The present invention relates to technical field of semiconductors, relate in particular to a kind of cmos image sensor and preparation method thereof.
Background technology
(CMOS Image Sensor CIS) rely on its manufacturing process and general integrated circuit standard technology flow process compatible strong, and (Charge Coupled Device CCD) has remarkable advantages to cmos image sensor than the existing charge coupled apparatus.Cmos image sensor does not exist that the volume in the CCD technology is big, power consumption is high, and inherent shortcomings such as poor compatibility can take full advantage of existing technological process and equipment on the contrary, and realizes integrating with related treatment circuit, has the level of integrated system of height.In addition, compare CCD, cmos image sensor has advantages such as volume is little, low in energy consumption, speed is fast, and is with low cost, is used widely in the photography and vedio recording product.
Traditional active pixel is to use photodiode as image sensing device.Common active pixel cell is by three transistors and a N
+/ P
-Photodiode constitutes, and this structure is fit to the CMOS manufacturing process of standard.In the spatial distribution design for the doping of photodiode, the designer must make the space charge region avoid the area that concentrate in complex centre such as crystal defect, to reduce the dark current of pixel.And along with the size of active pixel reduces gradually, the trap capacity that photodiode holds electronics also diminishes thereupon, so catching with the conversion of photosignal and transmission of light is produced certain influence.
For fear of above-mentioned defective, adopt following two kinds of designs usually for cmos image sensor now: one, combine with photodiode and 3 transistors of standard CMOS process compatibility, guarantee the area of photodiode with this.In the pixel operation of described 3T structure, by opening reset transistor, the grid of amplifier transistor in the pixel is charged to high potential in advance, thereby makes the P-N knot of photodiode be in anti-state partially.After reset transistor is closed, the electronics that anti-PN junction partially produces in the silicon body because of photoelectric effect by collection in the photodiode, and repel corresponding with it hole, the grid potential of the amplifier transistor that is attached thereto is descended.They are two years old, not with the pinned photodiode of the high trap capacity of having of standard CMOS process compatibility is combined with 4 transistors has a dot structure than low-dark current, described pinned photodiode comprises the N-layer, and is formed on the P+ articulamentum that forms on the described N-layer.Described 4T structure is when illumination, and photodiode produces electric charge at the N-place, and this moment, transfering transistor was in closed condition.Transfering transistor is opened then, and the electric transmission that is stored in the photodiode is arrived floating node, and after the transmission, transfering transistor is closed, and waits for entering of illumination next time.Charge signal on floating node is used for adjusting amplifier transistor subsequently.After reading, the reset transistor that has reset gate resets to a reference voltage with floating point.
But the dark current in the 3T structure has limited detection limit and the dynamic range of imageing sensor.In the 4T structure, electronics can not be transferred to the picture delay of floating node fully in the photodiode that the knot distribution problem causes in the pinned diode.
In order to reduce or to suppress the defective that pinned photodiode produces in the 4T structure, guarantee the faster and more transfering transistor that passes through of electronics that photodiode produces, Chinese patent CN200510126641.2 utilizes the dual injection of indium and boron to form P
+Articulamentum.The indium layer of low diffusivity, high concentration can stop that depletion layer extends upwardly to the surface.The variable concentrations of boron and indium and diffusivity form transverse gradients, the electric field that this gradient has makes electronics pass transfer pipeline from the sensitization side and arrives the drain side (being floating point) of transmission, thereby the gathering speed of electronics is increased, reduce the photoelectron that is trapped in the photodiode.But, because the quality of boron itself is little, and is subjected to Temperature Influence and can distributes again, cause the overcompensation of boron in photodiode, make the potential barrier between photodiode and the transfer pipeline bigger.
So at the problem that prior art exists, this case designer relies on the industry experience for many years of being engaged in, the active research improvement is so there has been a kind of cmos image sensor of the present invention and preparation method thereof.
Summary of the invention
The present invention be directed in the prior art, dark current has limited detection limit and the dynamic range of imageing sensor in traditional 3T structure; In the 4T structure, the defectives such as picture delay that electronics can not be transferred to floating node fully in the photodiode that causes of knot distribution problem in the pinned diode provide a kind of cmos image sensor.
The present invention's another purpose is in the prior art, and dark current has limited detection limit and the dynamic range of imageing sensor in traditional 3T structure; In the 4T structure, the defectives such as picture delay that electronics can not be transferred to floating node fully in the photodiode that causes of knot distribution problem in the pinned diode provide a kind of preparation method of cmos image sensor.
In order to address the above problem, the invention provides a kind of cmos image sensor, described cmos image sensor, comprise the photodiode that is arranged in the described Semiconductor substrate, transfering transistor, reset transistor, first floating node, second floating node, and the isolation structure that is used for the device electrical isolation, wherein, described photodiode has first area and the second area of at least two different indium doping contents, and the indium doping content of first area that is positioned at described transfering transistor far-end is less than the indium doping content of the second area that is positioned at described transfering transistor near-end.
Alternatively, described Semiconductor substrate is the p-type substrate.
Alternatively, described first floating node and second floating node are the N+ doped region.
Alternatively, form the internal electric field that is pointed to described first area by described second area in the described photodiode.
Be to realize the present invention's another purpose, the invention provides a kind of preparation method of cmos image sensor, described method comprises,
Execution in step S1: form the conventional structure photodiode;
Execution in step S2: control ion implantation angle, described conventional structure photodiode is carried out at least twice ion to be injected, thereby make described photodiode have first area at least and the second area of different indium doping contents, and the indium doping content of first area that is positioned at described transfering transistor far-end is less than the indium doping content of the second area that is positioned at described transfering transistor near-end.
Alternatively, described step S2 further comprises,
Execution in step S21: be mask with described photoresistance, the setting regions of described conventional structure photodiode carried out first time ion inject that ion injected and adopted vertical implant angle described first time;
Execution in step S22: be mask with described photoresistance, the setting regions of described conventional structure photodiode carried out second time ion inject that ion injected to adopt and was the α subscript with described Semiconductor substrate and goes into described second time.
Alternatively, described α angle is adjusted according to the width designing requirement of doped region.
Alternatively, the energy that the described first time, ion injected is 30～120KeV, and the concentration that the described first time, ion injected is 6 * 10
11～10 * 10
12Individual/cm
2
Alternatively, the energy that the described second time, ion injected is 30～120KeV, and the concentration that the described second time, ion injected is 6 * 10
11～10 * 10
12Individual/cm
2
In sum, cmos image sensor of the present invention adopts at least twice different angles ion to inject, and the capture-effect of utilizing ion to inject, have first area and the second area of different indium doping contents thereby form at described photodiode, and the indium doping content of first area that is positioned at described transfering transistor far-end is less than the indium doping content of the second area that is positioned at described transfering transistor near-end.When described photodiode inserts closed circuit, in described photodiode, just form the internal electric field E that is pointed to described first area by described second area, thereby improved photoelectronic transmission speed, reduced the photoelectron that is trapped in the photodiode, improve described photodiode and collected photoelectronic efficient, also reduced the phenomenon of picture delay or information dropout.
Description of drawings
Figure 1 shows that the structural representation of cmos image sensor of the present invention;
Figure 2 shows that the schematic diagram of the photodiode indium doping for the first time of cmos image sensor;
Figure 3 shows that the schematic diagram of the photodiode indium doping for the second time of cmos image sensor.
Embodiment
By the technology contents, the structural feature that describe the invention in detail, reached purpose and effect, described in detail below in conjunction with embodiment and conjunction with figs..
See also Fig. 1, Figure 1 shows that the structural representation of cmos image sensor of the present invention.Shown in cmos image sensor 1 comprise photodiode 11, transfering transistor 12, reset transistor 13, first floating node 14, second floating node 15 that is arranged in the described Semiconductor substrate 10, and the isolation structure 16 that is used for the device electrical isolation, wherein, described photodiode 11 has first area 111 and the second area 112 of at least two different indium doping contents, and the indium doping content of first area 111 that is positioned at described transfering transistor 12 far-ends is less than the indium doping content of the second area 112 that is positioned at described transfering transistor 12 near-ends.In the present invention, definition " far-end ", " near-end " are the described relatively transfering transistor 12 residing positions, zone of described different indium doping contents.
In the present invention, described Semiconductor substrate 10 is the p-type substrate.Described first floating node 14 and second floating node 15 are N
+Doped region.Described photodiode 11 is used for collecting photoelectron, reads light signal; Described transfering transistor 12 is used for the signal of described photodiode 11 outputs is transferred to first floating node 14.
In the present invention, because the first area 111 of described photodiode 11 has different indium doping contents with second area 112, then in working order down, the first area 11 of described photodiode 11 has different electromotive forces with second area 112.Particularly, be positioned at the indium doping content of first area 111 of described transfering transistor 12 far-ends less than the indium doping content of the second area 112 that is positioned at described transfering transistor 12 near-ends, then when described photodiode 11 inserts closed circuit, in described photodiode 11, just form the internal electric field E that is pointed to described first area 111 by described second area 112.Because the driving of internal electric field E, photoelectron in the described photodiode 11 is further to described transfering transistor 12 directions motion, thereby improved photoelectronic transmission speed, reduced the photoelectron that is trapped in the photodiode 11, particularly effectively accelerated to be positioned at the photoelectron transmission at 111 places, first area of described photodiode 11 far-ends, improve described photodiode 11 and collected photoelectronic efficient, also reduced the phenomenon of picture delay or information dropout.
Significantly, in the present invention, enumerate first area 111 and second area 112 that described photodiode 11 has different indium doping contents, the quantity in described different indium doping contents zone should not be considered as the restriction to technical solution of the present invention.As those skilled in the art will readily understand ground, described photodiode 11 also can comprise three or three above zoness of different of indium doping content distribution gradient.Regional number with different indium doping contents does not influence the formation of its internal electric field, and can and then photoelectronic transmission be played the driving effect.Particularly, described indium doping content distribution gradient refers to be positioned at the indium doping content in zone of described transfering transistor 12 far-ends less than the indium doping content in the zone that is positioned at described transfering transistor 12 near-ends.
See also Fig. 2, Fig. 3, and in conjunction with consulting Fig. 1, Figure 2 shows that the schematic diagram of the photodiode indium doping for the first time of cmos image sensor.Figure 3 shows that the schematic diagram of the photodiode indium doping for the second time of cmos image sensor.The preparation method of described cmos image sensor may further comprise the steps,
Execution in step S1: form conventional structure photodiode 11a; So-called conventional structure photodiode 11a is doping content not with the big or small transistor that changes of its distance with described transfering transistor 12.
Execution in step S2: control ion implantation angle, described conventional structure photodiode 11a is carried out repeatedly ion to be injected, thereby make described photodiode 11 have first area at least 111 and the second area 112 of different indium doping contents, and the indium doping content of first area 111 that is positioned at described transfering transistor 12 far-ends is less than the indium doping content of the second area 112 that is positioned at described transfering transistor 12 near-ends.
Particularly, described step S2 further comprises,
Execution in step S21: be mask with described photoresistance 17, the setting regions of described conventional structure photodiode 11a carried out first time ion inject.Wherein, vertical implant angle is adopted in the described ion injection first time.The energy that the described first time, ion injected is 30～120KeV, and the concentration that the described first time, ion injected is 6 * 10
11～10 * 10
12Individual/cm
2
Execution in step S22: be mask with described photoresistance 17, the setting regions of described conventional structure photodiode 11 carried out second time ion inject.Wherein, for the second time ion injects to adopt and is the α subscript with described Semiconductor substrate 10 and goes into.The energy that the described second time, ion injected is 30～120KeV, and the concentration that the described first time, ion injected is 6 * 10
11～10 * 10
12Individual/cm
2
Described α angle can be adjusted according to the width designing requirement of doped region.Because the shadow effect that described photoresistance 17 tilts, make the indium doping content of second area 112 of described transfering transistor 12 1 ends of being bordering on of described photodiode 11 be higher than the indium doping content away from the first area 111 of described transfering transistor 12 1 ends of described photodiode 11.
Particularly, because the implant angle that twice injection adopted there are differences, and the capture-effect of ion injection, have first area at least 111 and the second area 112 of different indium doping contents thereby form at described photodiode 11, and the indium doping content of first area 111 that is positioned at described transfering transistor 12 far-ends is less than the indium doping content of the second area 112 that is positioned at described transfering transistor 12 near-ends.When described photodiode 11 inserts closed circuit, in described photodiode 11, just form the internal electric field E that is pointed to described first area 111 by described second area 112.Because the driving of internal electric field E, photoelectron in the described photodiode 11 is further to described transfering transistor 12 directions motion, thereby improved photoelectronic transmission speed, reduced the photoelectron that is trapped in the photodiode 11, particularly effectively accelerated to be positioned at the photoelectron transmission at 111 places, first area of described photodiode 11 far-ends, improve described photodiode 11 and collected photoelectronic efficient, also reduced the phenomenon of picture delay or information dropout.
In sum, cmos image sensor of the present invention adopts at least twice different angles ion to inject, and the capture-effect of utilizing ion to inject, have first area and the second area of different indium doping contents thereby form at described photodiode, and the indium doping content of first area that is positioned at described transfering transistor far-end is less than the indium doping content of the second area that is positioned at described transfering transistor near-end.When described photodiode inserts closed circuit, in described photodiode, just form the internal electric field E that is pointed to described first area by described second area, thereby improved photoelectronic transmission speed, reduced the photoelectron that is trapped in the photodiode, improve described photodiode and collected photoelectronic efficient, also reduced the phenomenon of picture delay or information dropout.
Those skilled in the art all should be appreciated that, under the situation that does not break away from the spirit or scope of the present invention, can carry out various modifications and variations to the present invention.Thereby, if when any modification or modification fall in the protection range of appended claims and equivalent, think that the present invention contains these modifications and modification.
Claims (9)
1. cmos image sensor, comprise the photodiode, transfering transistor, reset transistor, first floating node, second floating node that are arranged in the described Semiconductor substrate, and the isolation structure that is used for the device electrical isolation, it is characterized in that, described photodiode has first area and the second area of at least two different indium doping contents, and the indium doping content of first area that is positioned at described transfering transistor far-end is less than the indium doping content of the second area that is positioned at described transfering transistor near-end.
2. cmos image sensor as claimed in claim 1 is characterized in that, described Semiconductor substrate is the p-type substrate.
3. cmos image sensor as claimed in claim 1 is characterized in that, described first floating node and second floating node are N
+Doped region.
4. cmos image sensor as claimed in claim 1 is characterized in that, forms the internal electric field that is pointed to described first area by described second area in the described photodiode.
5. the preparation method of a cmos image sensor as claimed in claim 1 is characterized in that, described method comprises,
Execution in step S1: form the conventional structure photodiode;
Execution in step S2: control ion implantation angle, described conventional structure photodiode is carried out at least twice ion to be injected, thereby make described photodiode have first area at least and the second area of different indium doping contents, and the indium doping content of first area that is positioned at described transfering transistor far-end is less than the indium doping content of the second area that is positioned at described transfering transistor near-end.
6. the preparation method of cmos image sensor as claimed in claim 5 is characterized in that, described step S2 further comprises,
Execution in step S21: be mask with described photoresistance, the setting regions of described conventional structure photodiode carried out first time ion inject that ion injected and adopted vertical implant angle described first time;
Execution in step S22: be mask with described photoresistance, the setting regions of described conventional structure photodiode carried out second time ion inject that ion injected to adopt and was the α subscript with described Semiconductor substrate and goes into described second time.
7. the preparation method of cmos image sensor as claimed in claim 6 is characterized in that, described α angle is adjusted according to the width designing requirement of doped region.
8. the preparation method of cmos image sensor as claimed in claim 6 is characterized in that, the energy that the described first time, ion injected is 30～120KeV, and the concentration that the described first time, ion injected is 6 * 10
11～10 * 10
12Individual/cm
2
9. the preparation method of cmos image sensor as claimed in claim 6 is characterized in that, the energy that the described second time, ion injected is 30～120KeV, and the concentration that the described second time, ion injected is 6 * 10
11～10 * 10
12Individual/cm
2
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310085156XA CN103208502A (en) | 2013-03-15 | 2013-03-15 | Complementary Metal-Oxide-Semiconductor Transistor (CMOS) image sensor and production method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310085156XA CN103208502A (en) | 2013-03-15 | 2013-03-15 | Complementary Metal-Oxide-Semiconductor Transistor (CMOS) image sensor and production method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN103208502A true CN103208502A (en) | 2013-07-17 |
Family
ID=48755673
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310085156XA Pending CN103208502A (en) | 2013-03-15 | 2013-03-15 | Complementary Metal-Oxide-Semiconductor Transistor (CMOS) image sensor and production method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103208502A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110444556A (en) * | 2019-08-30 | 2019-11-12 | 上海华力微电子有限公司 | The forming method of cmos sensor and cmos sensor |
| CN111092089A (en) * | 2018-10-24 | 2020-05-01 | 天津大学青岛海洋技术研究院 | CMOS image sensor pixel structure for large photosensitive area charge fast transfer |
| CN114339087A (en) * | 2020-09-30 | 2022-04-12 | 思特威(上海)电子科技股份有限公司 | TOF image sensor pixel structure and ranging system |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060046338A1 (en) * | 2004-08-24 | 2006-03-02 | Inna Patrick | Method of fabricating a storage gate pixel design |
| CN1828916A (en) * | 2005-02-28 | 2006-09-06 | 美格纳半导体有限会社 | Complementary metal-oxide-semiconductor image sensor and method for fabricating the same |
| CN102222679A (en) * | 2011-07-05 | 2011-10-19 | 上海宏力半导体制造有限公司 | CMOS (complementary metal-oxide-semiconductor transistor) image sensor and manufacturing method thereof |
-
2013
- 2013-03-15 CN CN201310085156XA patent/CN103208502A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060046338A1 (en) * | 2004-08-24 | 2006-03-02 | Inna Patrick | Method of fabricating a storage gate pixel design |
| CN1828916A (en) * | 2005-02-28 | 2006-09-06 | 美格纳半导体有限会社 | Complementary metal-oxide-semiconductor image sensor and method for fabricating the same |
| CN102222679A (en) * | 2011-07-05 | 2011-10-19 | 上海宏力半导体制造有限公司 | CMOS (complementary metal-oxide-semiconductor transistor) image sensor and manufacturing method thereof |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111092089A (en) * | 2018-10-24 | 2020-05-01 | 天津大学青岛海洋技术研究院 | CMOS image sensor pixel structure for large photosensitive area charge fast transfer |
| CN110444556A (en) * | 2019-08-30 | 2019-11-12 | 上海华力微电子有限公司 | The forming method of cmos sensor and cmos sensor |
| CN114339087A (en) * | 2020-09-30 | 2022-04-12 | 思特威(上海)电子科技股份有限公司 | TOF image sensor pixel structure and ranging system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN209389038U (en) | Image sensor with a plurality of pixels | |
| US9443900B2 (en) | Pixel with multigate structure for charge storage or charge transfer | |
| CN103904092B (en) | Method for improving electron transfer efficiency of silicon-based CMOS image sensor | |
| CN103227183B (en) | A kind of method suppressing back-illuminated cmos image sensors electrical mutual disturbance | |
| CN103346161A (en) | Method for improving picture signal quality of overlapping backside illuminated CMOS imaging sensor | |
| CN103811510B (en) | Pixel cell of imageing sensor and forming method thereof | |
| US11315969B2 (en) | Buried tri-gate fin vertical gate structure and method for making the same | |
| CN103152529A (en) | Pixel structure for improving charge transfer efficiency and reducing dark current and working method of pixel structure | |
| CN103500750B (en) | The structure of a kind of cmos image sensor active pixel and manufacture method thereof | |
| CN105161462A (en) | Method for improving carrier transmission efficiency of backside illumination image sensor | |
| CN103208502A (en) | Complementary Metal-Oxide-Semiconductor Transistor (CMOS) image sensor and production method thereof | |
| CN103413816B (en) | Dot structure of cmos image sensor and forming method thereof | |
| CN103413817B (en) | Dot structure of cmos image sensor and forming method thereof | |
| CN104465689A (en) | High-dynamic range image sensor pixel unit and preparation method thereof | |
| CN203661181U (en) | Image sensor | |
| CN103139497B (en) | The active pixel and cmos image sensor of cmos image sensor | |
| CN102332458B (en) | The using method of imageing sensor and imageing sensor, manufacture method | |
| CN102222678A (en) | CMOS (Complementary Metal Oxide Semiconductor) image sensor and forming method thereof | |
| CN101304035B (en) | Image sensor and method for forming the same | |
| CN102820313A (en) | Complementary Complementary Metal Oxide Semiconductor (CMOS) imaging sensor | |
| CN203826392U (en) | Back-illuminated CMOS image sensor | |
| CN101304036B (en) | Image sensor and method for forming the same | |
| CN101567337A (en) | CMOS image sensor and preparation method thereof | |
| CN106024822B (en) | Cmos image sensor and its manufacturing method with double epitaxial layer structures | |
| Li et al. | Collection efficiency and charge transfer optimization for a 4-T pixel with multi n-type implants |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C12 | Rejection of a patent application after its publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20130717 |