JPS63172462A - Manufacture of image sensor - Google Patents
Manufacture of image sensorInfo
- Publication number
- JPS63172462A JPS63172462A JP62004679A JP467987A JPS63172462A JP S63172462 A JPS63172462 A JP S63172462A JP 62004679 A JP62004679 A JP 62004679A JP 467987 A JP467987 A JP 467987A JP S63172462 A JPS63172462 A JP S63172462A
- Authority
- JP
- Japan
- Prior art keywords
- image sensor
- layer
- insulating layer
- forming
- dark current
- 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
- 238000004519 manufacturing process Methods 0.000 title claims description 5
- 229910021417 amorphous silicon Inorganic materials 0.000 claims abstract description 8
- 239000000758 substrate Substances 0.000 claims abstract description 7
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 claims description 4
- 239000011521 glass Substances 0.000 claims description 3
- 238000000151 deposition Methods 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 6
- 238000005229 chemical vapour deposition Methods 0.000 abstract description 4
- 238000005516 engineering process Methods 0.000 abstract description 4
- 229910004205 SiNX Inorganic materials 0.000 abstract 2
- 238000001259 photo etching Methods 0.000 abstract 2
- 238000001704 evaporation Methods 0.000 abstract 1
- 239000000126 substance Substances 0.000 abstract 1
- 238000001771 vacuum deposition Methods 0.000 abstract 1
- 239000011651 chromium Substances 0.000 description 4
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 238000000206 photolithography Methods 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910052581 Si3N4 Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 229910017875 a-SiN Inorganic materials 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- AQCDIIAORKRFCD-UHFFFAOYSA-N cadmium selenide Chemical compound [Cd]=[Se] AQCDIIAORKRFCD-UHFFFAOYSA-N 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 229910003437 indium oxide Inorganic materials 0.000 description 1
- PJXISJQVUVHSOJ-UHFFFAOYSA-N indium(iii) oxide Chemical compound [O-2].[O-2].[O-2].[In+3].[In+3] PJXISJQVUVHSOJ-UHFFFAOYSA-N 0.000 description 1
- 230000010365 information processing Effects 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229910000077 silane Inorganic materials 0.000 description 1
- 150000003376 silicon Chemical class 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 description 1
- 229910052814 silicon oxide Inorganic materials 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
Classifications
-
- 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
- H01L27/14643—Photodiode arrays; MOS imagers
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)
Abstract
Description
【発明の詳細な説明】
〔概要〕
表面導光形イメージセンサ暗電流を低減する方法として
ダイオードの光電層を形成する非晶質水素化シリコン層
上に透明絶縁層を形成し、ダイオード形成部を窓開けし
たる後、該透明絶縁層上に共通透明電極を形成するイメ
ージセンサの製造方法。[Detailed Description of the Invention] [Summary] As a method for reducing the dark current of a surface light guiding type image sensor, a transparent insulating layer is formed on an amorphous hydrogenated silicon layer that forms a photoelectric layer of a diode, and a diode forming part is formed. A method for manufacturing an image sensor, comprising forming a common transparent electrode on the transparent insulating layer after opening a window.
本発明は暗電流を低減したイメージセンサの製造方法に
関する。The present invention relates to a method of manufacturing an image sensor with reduced dark current.
イメージセンサ（１＋＊ａｇｅ−ｓｅｎｓｏｒ）は光学
的な画像を電気信号に変換する装置であり、信頼性、性
能、小°形軽量化などの点から従来の真空管式のものに
代わって固体化したものが用いられている。An image sensor (1+*age-sensor) is a device that converts an optical image into an electrical signal, and it is a solid-state image sensor that replaces the conventional vacuum tube type in terms of reliability, performance, small size and weight reduction. something is being used.
そして、この構造は非晶質水素化シリコン（以下略して
ａ−５ｔ：Ｈ）或いはセレン化カドミウム（Ｃｄ Ｓｅ
）などの光電材料を用いて光電素子が形成されており、
この光電素子が多数−列に配列してイメージセンサが形
成されている。This structure is based on amorphous silicon hydride (hereinafter abbreviated as a-5t:H) or cadmium selenide (CdSe
) Photoelectric elements are formed using photoelectric materials such as
An image sensor is formed by arranging many photoelectric elements in rows.
そして、使用法としては発光ダイオード（ＬＥＤ）で原
稿を照明し、この原稿からの反射光をセルフォックレン
ズなどを用いて等倍に結像させ、これを光電素子が受光
して電気信号に変換している。The method of use is to illuminate the original with a light-emitting diode (LED), and use a SELFOC lens to form an image at the same magnification as the light reflected from the original, which is then received by a photoelectric element and converted into an electrical signal. are doing.
すなわち、イメージセンサは紙送りされてくる原稿を電
気的に走査し、各光電素子が検出している原稿の白黒に
対応する電気信号を順次シフトレジスタに伝送して情報
処理を行うものである。That is, the image sensor electrically scans a fed document, and sequentially transmits electrical signals corresponding to black and white of the document detected by each photoelectric element to a shift register to perform information processing.
本発明は光電材料としてａ−Ｓｉ：Ｈを用いるイメージ
センサの性能向上に関するものである。The present invention relates to improving the performance of an image sensor using a-Si:H as a photoelectric material.
第３図は従来の導光形イメージセンサの断面図で、同図
（Ａ）は正面図、また同図（Ｂ）はＸ−Ｘ′位置の断面
を示す側面図である。FIG. 3 is a sectional view of a conventional light guide type image sensor, in which (A) is a front view, and (B) is a side view showing a cross section taken along line X-X'.
すなわち、ガラス或いはセラミックからなる絶縁基板１
上にクローム（Ｃｒ）などの金属よりなる個別電極２が
パターン形成されており、この上に光電材料であるａ−
Ｓｔ：８層３がプラズマ化学気相成長法（以下略してＰ
−ＣＶＤ法）などの方法を用いて形成されており、更に
この上に酸化インジウム（ＩｎｚＯｓ）と酸化錫（Ｓｎ
ｏｗ）の固溶体（通称ＩＴＯ）からなる共通透明電極４
が形成され、これにより多数の光電素子からなるイメー
ジセンサが形成されている。That is, an insulating substrate 1 made of glass or ceramic
Individual electrodes 2 made of metal such as chromium (Cr) are patterned on top, and a-
St: 8 Layer 3 was formed using plasma chemical vapor deposition method (hereinafter abbreviated as P).
-CVD method), and on top of this, indium oxide (InzOs) and tin oxide (Sn
A common transparent electrode 4 made of a solid solution (commonly known as ITO) of
is formed, thereby forming an image sensor consisting of a large number of photoelectric elements.
ここで、個別電極２と共通透明電極４は共に金属層から
形成されているためにａ−５ｔｓＨ層３との界面にショ
ットキ・バリアを生じているが、個別電極２からａ−５
ｔ：８層３への電流方向が順方向となるように電圧を印
加する構成をとるため、この界面での電圧降下は無視す
ることができ、このため個別電極２はオーミック個別電
極とも言われている。Here, since the individual electrode 2 and the common transparent electrode 4 are both formed of metal layers, a Schottky barrier is generated at the interface with the a-5tsH layer 3, but from the individual electrode 2 to the a-5
t: 8 Since voltage is applied so that the current direction to layer 3 is in the forward direction, the voltage drop at this interface can be ignored, and for this reason, individual electrode 2 is also called an ohmic individual electrode. ing.
一方、°共通透明電極４には逆方向に電圧が印加されて
おり、微少な逆方向電流（暗電流）が流れているが、両
者の接合部に形成されているバリア（基層）に光が投射
するとキャリアの光増倍により逆方向電流が増加してい
る（明電流）。On the other hand, a voltage is applied to the common transparent electrode 4 in the opposite direction, and a minute reverse current (dark current) flows, but light does not reach the barrier (base layer) formed at the junction between the two. When projected, the reverse current increases due to photomultiplication of carriers (bright current).
かかる動作をするイメージセンサにおいて、各光電素子
は明暗電流比がなるべく大きく形成されていることが必
要である。In an image sensor that operates in this manner, each photoelectric element must be formed to have a bright to dark current ratio as large as possible.
ここで、イメージセンサは形成後に２００〜３００℃の
熱処理を行って、電気的特性を安定化する処理が必要で
あるが、この処理により共通透明電極４を形成している
ＩＴＯのＩｎ原子やＳｎ原子がａ −５ｉ：８層３の中
に拡散して特性を劣化させており、そのために暗電流が
大きいと云う問題があった。Here, the image sensor requires heat treatment at 200 to 300° C. after formation to stabilize its electrical characteristics, but this treatment removes the In atoms and Sn of the ITO forming the common transparent electrode 4. There was a problem that atoms diffused into the a-5i:8 layer 3 and deteriorated the characteristics, resulting in a large dark current.
以上記したように従来の導光形イメージセンサにおいて
は共通当面電極４を構成しているＩｎ原子やＳｎ原子が
ａ−５ｔ：８層３の中に拡散して特性を劣化させており
、これにより光電素子の暗電流が大きく、明暗電流比が
充分にとれないことが問題である。As mentioned above, in the conventional light guide type image sensor, the In atoms and Sn atoms that constitute the common temporary electrode 4 diffuse into the a-5t:8 layer 3 and deteriorate the characteristics. The problem is that the dark current of the photoelectric element is large due to this, and a sufficient bright-to-dark current ratio cannot be obtained.
上記の問題は絶縁基板上にオーミック個別電極を形成し
たる後、引き続いてａ−５ｔ：Ｈ層を堆積し、該層上に
共通透明電極を形成してなる表面導光形イメージセンサ
において、
前記ａ−５ｉ：Ｈ層上に透明絶縁層を形成し、ダイオー
ド形成部を窓開けしたる後、該透明絶縁層上に前記の共
通透明電極を形成するイメージセンサの製造方法により
解決することができる。The above problem can be solved in a surface light guiding type image sensor in which an ohmic individual electrode is formed on an insulating substrate, then an a-5t:H layer is deposited, and a common transparent electrode is formed on the layer. a-5i: The problem can be solved by an image sensor manufacturing method in which a transparent insulating layer is formed on the H layer, a window is opened in the diode forming part, and then the above-described common transparent electrode is formed on the transparent insulating layer. .
本発明は今までＩｎ原子やＳｎ原子のａ−３ｉ：Ｈ層へ
の拡散によってａ−３ｉｓＨ層を劣化させると同時に実
質的に共通透明電極４の面積を増大させており、これに
より暗電流の増加を来していることから、共通透明電極
４とａ−Ｓｉ：８層３との接触面積を規制するものであ
る。Until now, the present invention has degraded the a-3isH layer by diffusing In atoms and Sn atoms into the a-3i:H layer, and at the same time substantially increased the area of the common transparent electrode 4, thereby reducing the dark current. This is because the contact area between the common transparent electrode 4 and the a-Si:8 layer 3 is regulated.
第１図は本発明に係るイメージセンサの断面図であって
、同図（Ａ）は正面図、また同図（Ｂ）はＸ−ｘ″線に
おける側面図である。FIG. 1 is a sectional view of an image sensor according to the present invention, in which (A) is a front view, and (B) is a side view taken along the line X-x''.
本発明は今まで、共通電極４とａ−Ｓｔ：８層３とが前
面的に接触していたのを改め、耐熱性をもつ透明絶縁層
５を介在させ、個別電極２の直上部のみ選択的に窓開け
することにより、この部分でのみ接触するようにしたも
のである。In the present invention, the common electrode 4 and the a-St:8 layer 3 have been in contact with each other from the front, but instead, a heat-resistant transparent insulating layer 5 is interposed, and only the upper part of the individual electrode 2 is selected. By opening the window at a certain point, contact is made only at this part.
このようにすると各光電素子の電極面積は窓の大きさに
規制できるため暗電流は減少し、−力投射光は透明絶縁
層５を通ってバリアに投射されるため、従来と同様にキ
ャリアの光増倍が行われ、従来どおりの明電流を得るこ
とができる。In this way, the electrode area of each photoelectric element can be regulated to the size of the window, so dark current is reduced. Photomultiplication is performed and a conventional bright current can be obtained.
ここで、透明絶縁層の構成材料としては酸化シリコン（
ＳｉＯ□）、酸窒化シリコン（ＳｉＯＮ） 、窒化シリ
コン（ａ−ＳｉＮｘ ）などの耐熱性無機絶縁物が適し
ている。Here, silicon oxide (
Heat-resistant inorganic insulators such as SiO□), silicon oxynitride (SiON), and silicon nitride (a-SiNx) are suitable.
第４図（Ａ）〜（Ｄ）は本発明の実施例を示すもので、
左図は正面断面図また右図はＸ−Ｘ″位置おける側断面
図である。FIGS. 4(A) to 4(D) show examples of the present invention,
The left figure is a front sectional view, and the right figure is a side sectional view taken along the line X-X''.
すなわち、絶縁基板１としてガラス基板を用い、個別電
極２としてはクロームＣｒを用い、真空蒸着法により２
０００人の厚さに膜形成し、写真蝕刻技術（フォトリソ
グラフィ）により電極パターンを形成した（以上同図Ａ
）。That is, a glass substrate is used as the insulating substrate 1, chromium Cr is used as the individual electrodes 2, and 2
A film was formed to a thickness of 1,000 mm, and an electrode pattern was formed using photolithography (see Figure A).
).
次に、シラン（Ｓｉｔｌｍ）と水素（Ｈ２）の混合ガス
を用いるプラズマ−化学気相成長法（Ｐ−ＣＶＤ法）に
よりａ−Ｓｉ：Ｈ層３を１μｍの厚さに形成した後、写
真蝕刻技術によりイメージセンサのパターン形成を行っ
た（以上同図Ｂ）。Next, an a-Si:H layer 3 was formed to a thickness of 1 μm by plasma-chemical vapor deposition (P-CVD) using a mixed gas of silane (Sitlm) and hydrogen (H2), and then photoetched. The pattern of the image sensor was formed using this technology (see Figure B).
次に、５ｉＨｔ＋Ｈｚおよびアンモニア（ＮＨｚ）より
なる混合ガスを用いるＰ−ＣＶＤ法によりａ−ＳｉＮｘ
膜を１０００人の厚さに形成した後、写真蝕刻技術によ
りａ−３ｉＮｘよりなり、゛光電素子のダイオード形成
部６を窓開けした透明絶縁層５をパターン形成した（以
上同図Ｃ）。Next, a-SiN
After the film was formed to a thickness of 1,000 mm, a transparent insulating layer 5 made of a-3iNx was patterned by photolithography, with a window opening for the diode forming portion 6 of the photoelectric element (see C in the same figure).
次に、マスク蒸着法によりＩＴＯを１０００人の厚さに
形成して共通透明電極４を形成した（以上同図Ｄ）。Next, a common transparent electrode 4 was formed by forming ITO to a thickness of 1000 mm using a mask vapor deposition method (see D in the same figure).
第２図はこのようにして形成したイメージセンサの整流
特性を示すもので、実線７で示す本発明を適用したイメ
ージセンサは破ｗＡ８に示す従来構造のものに較べ、暗
電流を二桁少なく抑えることができる。Figure 2 shows the rectification characteristics of the image sensor formed in this way, and the image sensor to which the present invention is applied, shown by the solid line 7, has a dark current that is two orders of magnitude lower than that of the conventional structure shown in Figure 8. be able to.
以上記したように本発明の実施により暗電流が少なく、
明暗電流比の大きなイメージセンサの実用化が可能とな
る。As described above, by implementing the present invention, there is less dark current,
It becomes possible to put into practical use an image sensor with a large bright-to-dark current ratio.
舅炉庁稠〒
第１図（Ａ）、（Ｂ）は本発明に係るイメージセンサの
断面図、
第２図はイメージセンサの電流−電圧特性、第３図（Ａ
）、 （Ｂ）は従来のイメージセンサの断面図、
第４図（Ａ）〜（Ｄ）は本発明の詳細な説明する断面図
、
である。
図において、
１は絶縁基板、 ２は個別電極、３はａ−Ｓ
ｉ：Ｈ層、 ４は共通透明電極、５は透明絶縁層、
である。
粂 ３ のFigure 1 (A) and (B) are cross-sectional views of the image sensor according to the present invention, Figure 2 is the current-voltage characteristics of the image sensor, and Figure 3 (A) is the cross-sectional view of the image sensor according to the present invention.
), (B) are cross-sectional views of a conventional image sensor, and FIGS. 4(A) to (D) are cross-sectional views explaining the present invention in detail. In the figure, 1 is an insulating substrate, 2 is an individual electrode, and 3 is a-S
i: H layer; 4: common transparent electrode; 5: transparent insulating layer. Kume 3
Claims (1)
引き続いて非晶質水素化シリコン層を堆積し、該層上に
共通透明電極を形成してなる表面導光形イメージセンサ
において、前記非晶質水素化シリコン層上に透明絶縁層
を形成して各光電素子のダイオード形成部を窓開けした
後、該透明絶縁層上に前記の共通透明電極を形成したこ
とを特徴とするイメージセンサの製造方法。After forming ohmic individual electrodes on the glass substrate,
Subsequently, in a surface light guiding type image sensor formed by depositing an amorphous silicon hydride layer and forming a common transparent electrode on the layer, a transparent insulating layer is formed on the amorphous silicon hydride layer. 1. A method of manufacturing an image sensor, comprising: opening a diode forming portion of each photoelectric element, and then forming the common transparent electrode on the transparent insulating layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62004679A JPS63172462A (en) | 1987-01-12 | 1987-01-12 | Manufacture of image sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62004679A JPS63172462A (en) | 1987-01-12 | 1987-01-12 | Manufacture of image sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63172462A true JPS63172462A (en) | 1988-07-16 |
Family
ID=11590578
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62004679A Pending JPS63172462A (en) | 1987-01-12 | 1987-01-12 | Manufacture of image sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63172462A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5132541A (en) * | 1990-01-27 | 1992-07-21 | U.S. Philips Corporation | Sensor matrix |
-
1987
- 1987-01-12 JP JP62004679A patent/JPS63172462A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5132541A (en) * | 1990-01-27 | 1992-07-21 | U.S. Philips Corporation | Sensor matrix |
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