JPH02218160A - Solid-state image sensing element - Google Patents
Solid-state image sensing elementInfo
- Publication number
- JPH02218160A JPH02218160A JP1039658A JP3965889A JPH02218160A JP H02218160 A JPH02218160 A JP H02218160A JP 1039658 A JP1039658 A JP 1039658A JP 3965889 A JP3965889 A JP 3965889A JP H02218160 A JPH02218160 A JP H02218160A
- Authority
- JP
- Japan
- Prior art keywords
- conductivity type
- region
- photodiode
- solid
- well
- 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
- 239000000758 substrate Substances 0.000 claims abstract description 9
- 239000004065 semiconductor Substances 0.000 claims abstract description 8
- 238000003384 imaging method Methods 0.000 claims description 4
- 239000012535 impurity Substances 0.000 claims 2
- 229910021420 polycrystalline silicon Inorganic materials 0.000 abstract description 7
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 4
- 239000010410 layer Substances 0.000 abstract description 4
- 229910052814 silicon oxide Inorganic materials 0.000 abstract description 4
- 239000011229 interlayer Substances 0.000 abstract description 3
- 229920002120 photoresistant polymer Polymers 0.000 abstract description 3
- 238000009792 diffusion process Methods 0.000 abstract description 2
- 230000003647 oxidation Effects 0.000 abstract description 2
- 238000007254 oxidation reaction Methods 0.000 abstract description 2
- 238000012216 screening Methods 0.000 abstract 2
- 239000004020 conductor Substances 0.000 abstract 1
- 238000000034 method Methods 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 238000003860 storage Methods 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 at least one potential-jump barrier or surface barrier, 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 or surface barrier
- H01L31/107—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier or surface barrier the potential barrier working in avalanche mode, e.g. avalanche photodiode
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は、固体撮像素子に関し、特に、フォトダイオー
ドに増倍機能を有せしめた固体撮像素子に間する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a solid-state image sensor, and particularly to a solid-state image sensor in which a photodiode has a multiplication function.
［従来の技術］ 従来の固体撮像素子の断面図を第２図に示す。[Conventional technology] FIG. 2 shows a cross-sectional view of a conventional solid-state image sensor.
同図において、Ｎ型半導体基板１１上にはＰウェル１２
が形成されており、該ウェル内には、フォトダイオード
の一方の領域であるＮ＋領域１３、Ｐ−トランスファ領
域１５およびＮ＋電荷転送領域１４が形成されており、
これらの各領域はチャネルストッパ１７によって分離さ
れている。Ｐウェル１２上には、シリコン酸化膜１８を
介して多結晶シリコンゲート１９が形成されており、そ
の上にはさらに眉間絶縁膜２１と遮光膜２０が形成され
ている。この固体撮像素子においては、Ｎ４領域に所定
時間蓄積された光電変換電荷は、多結晶シリコンゲート
２０に読み出しパルスを印加することによりＰ−トラン
スファ領域１５を介してＮ＋電荷転送領域１４へ移送さ
れ、その後、この電荷転送領域を出力側へ向って転送さ
れる。In the figure, a P well 12 is placed on an N type semiconductor substrate 11.
is formed, and in the well, an N+ region 13, which is one region of the photodiode, a P-transfer region 15, and an N+ charge transfer region 14 are formed,
Each of these regions is separated by a channel stopper 17. A polycrystalline silicon gate 19 is formed on the P-well 12 via a silicon oxide film 18, and a glabella insulating film 21 and a light shielding film 20 are further formed on the polycrystalline silicon gate 19. In this solid-state imaging device, photoelectric conversion charges accumulated in the N4 region for a predetermined period of time are transferred to the N+ charge transfer region 14 via the P- transfer region 15 by applying a read pulse to the polycrystalline silicon gate 20. Thereafter, the charge is transferred toward the output side through this charge transfer region.
［発明が解決しようとする問題点］
上述した固体撮像素子においては、フォトダイオードが
増幅機能あるいは増倍機能を有していなかったので、照
度の低いところで使用した場合には、発生電荷が不足し
て鮮明な映像が得られなかった。[Problems to be Solved by the Invention] In the above-mentioned solid-state image sensor, the photodiode does not have an amplification function or a multiplication function, so when used in a place with low illuminance, there is a problem that the generated charge is insufficient. I couldn't get a clear image.
［問題点を解決するための手段］
本発明による固体撮像素子は、入射光の強さに応じた信
号電荷を発生するフォトダイオードと、該フォトダイオ
ードに発生した信号電荷を転送するＣＣＤと、基板上に
絶縁膜を介して形成されたゲート電極と遮光膜とを備え
たものであって、前記フォトダイオードがアバランシェ
フォトダイオードとなされている。[Means for Solving the Problems] A solid-state imaging device according to the present invention includes a photodiode that generates a signal charge according to the intensity of incident light, a CCD that transfers the signal charge generated in the photodiode, and a substrate. The photodiode is provided with a gate electrode and a light-shielding film formed thereon via an insulating film, and the photodiode is an avalanche photodiode.
［実施例］
次に、本発明の実施例について、図面を参照して説明す
る。[Example] Next, an example of the present invention will be described with reference to the drawings.
第１図は、本発明の一実施例を示す断面図である。この
構造の固体撮像素子を製造するには、予めＮ型半導体基
板１１上に、将来アバランシェフォトダイオードの空乏
層の伸びを限定する領域となるＰ４領域１２を形成して
おく、その後、半導体エピタキシャル層を形成し、フォ
トレジスト工程、イオン注入工程等を経てＰウェル１３
を形成する。さらに、Ｐウェル１３中に、アバランシェ
フォトダイオードの一部となるＮ“領域１４、ＣＣＤ部
となるＮ＋電荷転送領域１５を形成する。FIG. 1 is a sectional view showing one embodiment of the present invention. To manufacture a solid-state image sensor with this structure, a P4 region 12, which will be a region that will limit the growth of a depletion layer of an avalanche photodiode in the future, is formed on an N-type semiconductor substrate 11 in advance, and then a semiconductor epitaxial layer is formed. The P-well 13 is formed through a photoresist process, an ion implantation process, etc.
form. Further, in the P well 13, an N" region 14 which becomes a part of an avalanche photodiode and an N+ charge transfer region 15 which becomes a CCD section are formed.
また、領域１４．１５間にＰ−トランスファ領域１６を
形成しさらに活性領域のまわりにチャネルストッパ１７
を形成する。続いて、酸化工程、ＣＶＤ工程、拡散工程
、フォトレジスト工程等を繰り返し、シリコン酸化膜１
８、多結晶シリコンゲート１９、遮光［２０および層間
絶縁膜２１を形成して固体撮像素子を製造する。Further, a P-transfer region 16 is formed between regions 14 and 15, and a channel stopper 17 is further formed around the active region.
form. Subsequently, oxidation process, CVD process, diffusion process, photoresist process, etc. are repeated to form silicon oxide film 1.
8. Polycrystalline silicon gate 19, light shielding film 20, and interlayer insulating film 21 are formed to manufacture a solid-state imaging device.
このようにしてつくられた固体撮像素子を動作させると
きには、遮光［２０には十分に高い電圧が印加されるも
のとする。その条件下では、Ｎ４領域１４は、遮光膜２
０および多結晶シリコンゲート１９の電位の影響を受け
て高い電圧に保持される。その結果、この領域とＰウェ
ル１３間に形成される空乏層には大きな加速電界が形成
され、この部分がアバランシェフォトダイオードとなさ
れる。そして、この場合に、Ｎ＋領域１４は逆バイアス
されて十分大きな電荷蓄積能力をもつようになる。When operating the solid-state image sensor manufactured in this manner, a sufficiently high voltage is applied to the light shielding circuit [20]. Under that condition, the N4 region 14 is
0 and is held at a high voltage under the influence of the potential of the polycrystalline silicon gate 19. As a result, a large accelerating electric field is formed in the depletion layer formed between this region and the P well 13, and this portion becomes an avalanche photodiode. In this case, the N+ region 14 is reverse biased and has a sufficiently large charge storage capacity.
［発明の効果］
以上説明したように、本発明は、固体撮像素子のフォト
ダイオードをアバランシェダイオードとしたものである
ので、本発明によれば、光電変換電荷の倍増作用によっ
て、入射光が微弱な場合であっても、大きな信号電荷量
を、すなわち大きな映像信号を得ることができる。[Effects of the Invention] As explained above, the present invention uses an avalanche diode as the photodiode of the solid-state image sensor. Even in such a case, a large signal charge amount, that is, a large video signal can be obtained.
２図は、従来例を示す断面図である。FIG. 2 is a sectional view showing a conventional example.
１１・・・Ｎ型半導体基板、 １２・・・Ｐ＋領域、１
３・・・Ｐウェル、 １４・・・Ｎ＋領領域 １５・・
・Ｎ＋電荷転送領域、 １６・・・Ｐ−トランファ領域
、１７・・・チャネルストッパ、 １８・・・シリコ
ン酸化膜、 １９・・・多結晶シリコンゲート、 ２０
・・・遮光膜、 ２１・・・層間絶縁膜。11...N-type semiconductor substrate, 12...P+ region, 1
3...P well, 14...N+ region 15...
・N+ charge transfer region, 16...P- transfer region, 17...channel stopper, 18...silicon oxide film, 19...polycrystalline silicon gate, 20
... Light-shielding film, 21... Interlayer insulating film.
Claims (1)
形成された第２導電型ウェルと、該第２導電型ウェル内
に形成された該第２導電型ウェルとともにフォトダイオ
ードを構成する不純物が高濃度にドープされた第１導電
型領域と、前記第２導電型ウェル内に形成された第１導
電型の電荷転送領域と、前記第１導電型領域の直下の前
記第１導電型半導体基板と前記第２導電型ウェルとの界
面に形成された不純物が高濃度にドープされた第２導電
型領域と、前記第２導電型ウェル上に第１の絶縁膜を介
して形成されたゲート電極と、さらにその上に第２の絶
縁膜を介して形成された前記第１導電型領域上に開口を
有する遮光膜とを具備する固体撮像素子において、前記
フォトダイオードがアバランシェフォトダイオードであ
ることを特徴とする固体撮像素子。A photodiode is constituted by a first conductivity type semiconductor substrate, a second conductivity type well formed on the first conductivity type semiconductor substrate, and the second conductivity type well formed in the second conductivity type well. a first conductivity type region heavily doped with impurities, a first conductivity type charge transfer region formed in the second conductivity type well, and the first conductivity type region immediately below the first conductivity type region. A second conductivity type region heavily doped with impurities is formed at the interface between the semiconductor substrate and the second conductivity type well, and a first insulating film is formed on the second conductivity type well. In the solid-state imaging device, the photodiode is an avalanche photodiode, and includes a gate electrode and a light-shielding film having an opening on the first conductivity type region formed thereon via a second insulating film. A solid-state image sensor characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1039658A JPH02218160A (en) | 1989-02-20 | 1989-02-20 | Solid-state image sensing element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1039658A JPH02218160A (en) | 1989-02-20 | 1989-02-20 | Solid-state image sensing element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02218160A true JPH02218160A (en) | 1990-08-30 |
Family
ID=12559187
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1039658A Pending JPH02218160A (en) | 1989-02-20 | 1989-02-20 | Solid-state image sensing element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02218160A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6392282B1 (en) | 1998-01-30 | 2002-05-21 | Hamamatsu Photonics K.K. | BiCMOS-integrated photodetecting semiconductor device having an avalanche photodiode |
-
1989
- 1989-02-20 JP JP1039658A patent/JPH02218160A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6392282B1 (en) | 1998-01-30 | 2002-05-21 | Hamamatsu Photonics K.K. | BiCMOS-integrated photodetecting semiconductor device having an avalanche photodiode |
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