GB2240429A - Method for manufacturing a photo diode for a CCD image sensor - Google Patents
Method for manufacturing a photo diode for a CCD image sensor Download PDFInfo
- Publication number
- GB2240429A GB2240429A GB9101669A GB9101669A GB2240429A GB 2240429 A GB2240429 A GB 2240429A GB 9101669 A GB9101669 A GB 9101669A GB 9101669 A GB9101669 A GB 9101669A GB 2240429 A GB2240429 A GB 2240429A
- Authority
- GB
- United Kingdom
- Prior art keywords
- type
- photo diode
- region
- substrate
- image sensor
- 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.)
- Withdrawn
Links
- 238000000034 method Methods 0.000 title claims abstract description 16
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 8
- 239000000758 substrate Substances 0.000 claims abstract description 26
- 150000002500 ions Chemical class 0.000 claims abstract description 7
- 238000005468 ion implantation Methods 0.000 claims description 3
- 108091006146 Channels Proteins 0.000 claims 3
- 108010075750 P-Type Calcium Channels Proteins 0.000 claims 1
- 239000012535 impurity Substances 0.000 description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 3
- 239000004411 aluminium Substances 0.000 description 3
- 229910052698 phosphorus Inorganic materials 0.000 description 3
- 239000011574 phosphorus Substances 0.000 description 3
- -1 phosphorus ions Chemical class 0.000 description 3
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 3
- 229920005591 polysilicon Polymers 0.000 description 3
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/08—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors
- H01L31/10—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof in which radiation controls flow of current through the device, e.g. photoresistors characterised by potential barriers, e.g. phototransistors
- H01L31/101—Devices sensitive to infrared, visible or ultraviolet radiation
- H01L31/102—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier
- H01L31/103—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier the potential barrier being of the PN homojunction type
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/12—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof structurally associated with, e.g. formed in or on a common substrate with, one or more electric light sources, e.g. electroluminescent light sources, and electrically or optically coupled thereto
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/148—Charge coupled imagers
- H01L27/14831—Area CCD imagers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
- H01L27/144—Devices controlled by radiation
- H01L27/146—Imager structures
- H01L27/148—Charge coupled imagers
- H01L27/14887—Blooming suppression
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/02—Details
- H01L31/0216—Coatings
- H01L31/02161—Coatings for devices characterised by at least one potential jump barrier or surface barrier
- H01L31/02162—Coatings for devices characterised by at least one potential jump barrier or surface barrier for filtering or shielding light, e.g. multicolour filters for photodetectors
- H01L31/02164—Coatings for devices characterised by at least one potential jump barrier or surface barrier for filtering or shielding light, e.g. multicolour filters for photodetectors for shielding light, e.g. light blocking layers, cold shields for infrared detectors
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Electromagnetism (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Solid State Image Pick-Up Elements (AREA)
- Light Receiving Elements (AREA)
- Transforming Light Signals Into Electric Signals (AREA)
Abstract
A method for manufacturing a photo diode of a CCD image sensor, comprises the steps of forming an oxide layer on an N<-> type substrate; implanting N<+> ions into a selected portion of the N<-> type substrate to form a N<+> type buried region; growing a P type epitaxial layer between the N<-> type substrate and the oxide layer; forming P<+> type channel stop regions by implanting P<+> ions into selected portions of the P type epitaxial layer; and forming a N<+> type photo diode region and a N<-> type well between the P<+> type channel stop regions, the N<+> photo diode being formed over the N<+> type buried region. <IMAGE>
Description
METHOD OF MANUFACTURING A PHOTO DIODE
FOR A CCD IMAGE SENSOR
The present invention relates to a method of manufacturing a photo diode for a charge coupled device (CCD) image sensor, and more particularly to a method for manufacturing a photo diode so as to limit over flow drain (OFD).
Conventionally photo diodes in CCD image sensors are constructed as shown in Fig. 1 or Fig. 3 and the process steps for fabricating the CCD image sensor of Fig. 1 are shown in Figs. 2A to 2D. As shown in Fig. 2A, a P type well region 2 is formed on N type substrate 1 and an oxide layer 3 is formed on the P type well region 2. P+ type regions 4 are formed by implanting phosphorus ions as shown in Fig. 2B. As shown in Fig. 2C, a N type photo diode region 5 and a N type well region 6 are formed therebetween, respectively. Polysilicon layer 7 and aluminium layer 8 are formed as shown in Fig. 2D. The process steps described above are inconvenient because it is difficult to adjust the depth below the N+ type photo diode region 5 of the P type well region 2 where it forms a cusp shape as shown.
The process steps for fabricating the CCD image sensor of Fig. 3 are shown in Fig. 4A to Fig. 4E. A shallow P type well region 9 is formed on N type substrate 1 and an oxide layer 3 is formed on the shallow P type well region 9 as shown in Fig. 4A. A deep P type well region 10 is formed in the shallow P type well region 9 leaving a shallow P type well region for forming the photo diode, as shown in Fig. 4B. Thus, the shallow P type well region 9 has a flat profile rather than being formed as a cusp shape as in Fig. 1. P+ type regions 4 are formed by implanting phosphorus ions as shown in Fig. 4C. After the ion implantation, a N type photo diode region 5 and a
N type well region 6 are formed therebetween as shown in
Fig. 4D, and then polysilicon layer 7 and aluminium layer 8 are formed as shown in Fig. 4E. The process step of Figs.
4A to 4E can be performed more easily than the process steps of Figs. 2A to 2D; but, there is a disadvantage in that the number of the process steps are increased.
The operation of the conventional structure will be explained referring to Fig 5. If electrons are accumulated in the N+ type photo diode region, the electron concentration in the N+ type photo diode is as shown by the curve. When a potential V1 is generated in the N+ type photo diode by applying threshold voltage
Vth to Transfer Gate TG, the electrons in the N+ type photo diode flow into the N type well region forming the vertical charge coupled device (VCCD).
As the impurity concentration in the N type substrate is higher than that of the P type well region, that of the P type well region being higher than that of
N type substrate, the electrons released by incident light may recombine in the N type region. As a result, it is difficult to limit OFD due to the process step used for forming the P type well region.
Accordingly, the present invention provides a method of manufacturing a photo diode for a CCD image sensor, comprising the steps of providing a N type substrate; forming an oxide layer on the N type substrate; implanting N+ ions into a selected portion of the N type substrate to form an N+ type buried region; growing a P type epitaxial layer between the N type substrate and the oxide layer; forming P+ type channel stop regions by implanting P ions into selected portions of the P type epitaxial layer; and forming a N+ type photo diode region and a N type well between the P+ type channel stop regions, the N type photo diode region being formed over the N+ type buried region.
In another aspect, the invention provides a photo diode for a CCD image sensor comprising a N type substrate; a P type epitaxially grown layer on the substrate; a N+ type buried region between the substrate and the P type epitaxial layer; P+ type channel stop regions in the P type epitaxial layer; a N+ type photo diode region and a N type well between the P+ type channel stop regions; the N type photo diode region being formed over the N+ buried region.
In the accompanying drawings:
Fig. 1 and Fig. 3 are cross sectional views of a photo diode in a conventional image sensor;
Fig. 2A to Fig. 2D are cross sectional views of the process steps for fabricating a CCD image sensor as in Fig.
1 Fig. 4A to Fig. 4E are cross sectional views of the process steps for fabricating a CCD image sensor as in Fig.
3;
Fig. 5 shows potential profiles under the photo diode of a conventional CCD image sensor;
Fig. 6 shows a cross sectional view of a photo diode in a CCD image sensor embodying the present invention;
Fig. 7A to Fig. 7D are cross sectional views of the process steps for fabricating the CCD image sensor as in
Fig. 6;
Fig. 8 shows potential profiles under the photo diode of a CCD image sensor embodying the present invention.
An example of the present invention will now be described with reference to Fig. 6 to Fig. 8 of the accompanying drawings.
As shown in Fig. 7A, oxide layer 22 is formed on
N type substrate 21 and then N+ ions are implanted into a selection portion of the N type substrate 21 to form a N+ type buried region 23.
A P type epitaxial layer 24 is then grown between the N type substrate 21 and the oxide layer 22 and type channel stop regions 24 are formed by implanting phosphorus ions into selected portions of the P type epitaxial layer 23 as shown in Fig. 7B.
N+ type photo diode region 26 and N type well 27 are formed between the P+ type regions 25, the type photo diode region 26 being formed over the N+ type buried region 23, as shown in Fig. 7C. Then, polysilicon layer 28 and aluminium layer 29 are formed thereon by known techniques as shown in Fig. 7(D).
In the CCD image sensor fabricated as described above, the potential profiles under the photo diode are represented by the curves b, c in Fig. 8 and the inclination of the curves b, c can be changed according to the concentration of the ion implantation in the buried region 23. Thus, it is easy to meet overflow drain requirements since the range of impurity concentration of the buried region is widely variable. As the P type epitaxial layer, instead of a P type well region, is formed on the N type substrate, the distribution of impurity concentration in the CCD region is uniform so that image character is improved, and it is possible to obtain almost the same effect as with N type substrate/N type epitaxial layer/P type well region structures which have typically been used to overcome the uniformity problem.
Another merit of the present invention is that it is easy to optimise the photo diode as the impurity concentrations of the N+ type photo diode region can be changed as required and the conventional P type well process is eliminated.
Claims (5)
1. A method of manufacturing a photo diode for a CCD image sensor, comprising the steps of providing a N type substrate; forming an oxide layer on the N type substrate; implanting N+ ions into a selected portion of the N type substrate to form an N+ type buried region; growing a P type epitaxial layer between the N type substrate and the oxide layer; forming P type channel stop regions by implanting P+ ions into selected portions of the P type epitaxial layer; and forming a N+ type photo diode region and a N type well between the P+ type channel stop regions, the N+ type photo diode region being formed over the N type buried region.
2. A method according to Claim 1, wherein the ion implantation to form the buried N+ type region is controlled to provide a predetermined potential profile under the N+ type photo diode region of the completed photo diode.
3. A photo diode for a CCD image sensor comprising a
N type substrate; a P type epitaxially grown layer on the substrate; a N+ type buried region between the substrate and the P type epitaxial layer; P+ type channel stop regions in the P type epitaxial layer; a N+ type photo diode region and a N type well between the type channel stop regions; the N+ type photo diode region being formed over the N+ buried region.
4. A method of manufacturing a photo diode for a CCD image sensor, substantially as hereinbefore described with reference to Figs. 6 to 8 of the accompanying drawings.
5. A photo diode for a CCD image sensor substantially as hereinbefore described with reference to and as illustrated in Figs. 6 to 8 of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019900000951A KR930000914B1 (en) | 1990-01-29 | 1990-01-29 | Photodiode over flow drain repression method from ccd imaging sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9101669D0 GB9101669D0 (en) | 1991-03-06 |
| GB2240429A true GB2240429A (en) | 1991-07-31 |
Family
ID=19295572
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9101669A Withdrawn GB2240429A (en) | 1990-01-29 | 1991-01-25 | Method for manufacturing a photo diode for a CCD image sensor |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPH04212460A (en) |
| KR (1) | KR930000914B1 (en) |
| DE (1) | DE4102591A1 (en) |
| GB (1) | GB2240429A (en) |
| NL (1) | NL9100082A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5416345A (en) * | 1991-03-28 | 1995-05-16 | Kabushiki Kaisha Toshiba | Solid-state image sensor with dark-current eliminator |
| US6579741B2 (en) * | 2000-07-20 | 2003-06-17 | Emcore Corporation | Monolithically integrated sensing device and method of manufacture |
| WO2005008748A1 (en) * | 2003-07-10 | 2005-01-27 | Zhao Linxin | An image sensor with a vertical overflow drain and short micro-lens to silicon distance |
| CN101262000B (en) * | 2007-03-06 | 2011-03-16 | 台湾积体电路制造股份有限公司 | Image sensor, its forming method and semiconductor device |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109817736A (en) * | 2019-01-23 | 2019-05-28 | 杭州电子科技大学 | A kind of pixel detector of clutter reduction and radiation hardened |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0285084A2 (en) * | 1987-03-31 | 1988-10-05 | Kabushiki Kaisha Toshiba | Solid state imaging device |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5755672A (en) * | 1980-09-19 | 1982-04-02 | Nec Corp | Solid-state image pickup device and its driving method |
-
1990
- 1990-01-29 KR KR1019900000951A patent/KR930000914B1/en not_active IP Right Cessation
-
1991
- 1991-01-17 NL NL9100082A patent/NL9100082A/en not_active Application Discontinuation
- 1991-01-25 GB GB9101669A patent/GB2240429A/en not_active Withdrawn
- 1991-01-29 JP JP3026788A patent/JPH04212460A/en active Pending
- 1991-01-29 DE DE4102591A patent/DE4102591A1/en not_active Ceased
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0285084A2 (en) * | 1987-03-31 | 1988-10-05 | Kabushiki Kaisha Toshiba | Solid state imaging device |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5416345A (en) * | 1991-03-28 | 1995-05-16 | Kabushiki Kaisha Toshiba | Solid-state image sensor with dark-current eliminator |
| US6579741B2 (en) * | 2000-07-20 | 2003-06-17 | Emcore Corporation | Monolithically integrated sensing device and method of manufacture |
| WO2005008748A1 (en) * | 2003-07-10 | 2005-01-27 | Zhao Linxin | An image sensor with a vertical overflow drain and short micro-lens to silicon distance |
| US6852565B1 (en) * | 2003-07-10 | 2005-02-08 | Galaxcore, Inc. | CMOS image sensor with substrate noise barrier |
| CN101262000B (en) * | 2007-03-06 | 2011-03-16 | 台湾积体电路制造股份有限公司 | Image sensor, its forming method and semiconductor device |
Also Published As
| Publication number | Publication date |
|---|---|
| NL9100082A (en) | 1991-08-16 |
| GB9101669D0 (en) | 1991-03-06 |
| KR930000914B1 (en) | 1993-02-11 |
| KR910015076A (en) | 1991-08-31 |
| JPH04212460A (en) | 1992-08-04 |
| DE4102591A1 (en) | 1991-08-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |