JPS6042988A - Solid-state image pickup device - Google Patents
Solid-state image pickup deviceInfo
- Publication number
- JPS6042988A JPS6042988A JP58151896A JP15189683A JPS6042988A JP S6042988 A JPS6042988 A JP S6042988A JP 58151896 A JP58151896 A JP 58151896A JP 15189683 A JP15189683 A JP 15189683A JP S6042988 A JPS6042988 A JP S6042988A
- Authority
- JP
- Japan
- Prior art keywords
- region
- solid
- diffusion layer
- stored
- junction
- 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
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims abstract description 6
- 229910052581 Si3N4 Inorganic materials 0.000 claims abstract description 4
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 claims abstract description 4
- 235000012239 silicon dioxide Nutrition 0.000 claims abstract description 3
- 239000000377 silicon dioxide Substances 0.000 claims abstract description 3
- 238000003384 imaging method Methods 0.000 claims description 8
- 239000007787 solid Substances 0.000 claims description 3
- 239000000758 substrate Substances 0.000 claims description 3
- 238000009792 diffusion process Methods 0.000 claims 11
- BPUBBGLMJRNUCC-UHFFFAOYSA-N oxygen(2-);tantalum(5+) Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ta+5].[Ta+5] BPUBBGLMJRNUCC-UHFFFAOYSA-N 0.000 claims 1
- 239000004065 semiconductor Substances 0.000 claims 1
- 229910001936 tantalum oxide Inorganic materials 0.000 claims 1
- 230000035945 sensitivity Effects 0.000 abstract description 6
- 239000003990 capacitor Substances 0.000 abstract description 5
- 230000010354 integration Effects 0.000 abstract description 4
- 238000009413 insulation Methods 0.000 abstract description 3
- 229910021420 polycrystalline silicon Inorganic materials 0.000 abstract description 3
- 229920005591 polysilicon Polymers 0.000 abstract description 3
- 229920006395 saturated elastomer Polymers 0.000 abstract 1
- 238000009738 saturating Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000002955 isolation Methods 0.000 description 3
- 229910000831 Steel Inorganic materials 0.000 description 2
- 230000003321 amplification Effects 0.000 description 2
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 241000277269 Oncorhynchus masou Species 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003287 optical effect Effects 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)
- Transforming Light Signals Into Electric Signals (AREA)
Abstract
Description
【発明の詳細な説明】
［発明の技術分野］
この発明は固体撮像装置に関し、特に、飽和信号レベル
の増大および画素の高集積化を図った固体＠像装置に関
するものである。DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a solid-state imaging device, and particularly to a solid-state @imaging device that increases the saturation signal level and increases the integration of pixels.
［従来技術］
第１図は従来のＭＯＳ形の固体！ｌ１ｌｉ装置の一例の
等価回路を示１図である。[Prior art] Figure 1 shows a conventional MOS solid state! FIG. 1 is a diagram showing an equivalent circuit of an example of the l1li device.
まず、第１図に示１等価回路の栴成と動作について説明
する。第１図において光電変換素子としてのフォトダイ
オード１１に光が入射すると、光電流が発生し、フォト
ダイオード１１の合釘１２に蓄えられる。そして、信号
読出し詩には、スイッチング素子としてのＭＯＳトラン
ジスタ１３がオンし、光電流を選択的に続出ず。First, the construction and operation of the equivalent circuit shown in FIG. 1 will be explained. In FIG. 1, when light enters a photodiode 11 as a photoelectric conversion element, a photocurrent is generated and stored in a dowel 12 of the photodiode 11. When the signal is read out, the MOS transistor 13 as a switching element is turned on, and the photocurrent is selectively output.
第２図は、第１図の等価回路で示した従来のＭＯ８形固
体瓶像装置の模式的断面図である。FIG. 2 is a schematic cross-sectional view of the conventional MO8 type solid bottle image device shown in the equivalent circuit of FIG.
次に、第２図に示す従来の固体撮像装置の構成について
説明する。第２図において、Ｎ型基板１上にフォトダイ
オードのアノードであるＰ型ウェル２が形成され、さら
にその上にフォトダイオードのカソードであると同時に
ＭＯＳトランジスタのソースでもあるＮ型領域３および
ＭＯＳ ｌ−ランジスタのビレ。インであるＮ型領域４
が形成される。Next, the configuration of the conventional solid-state imaging device shown in FIG. 2 will be explained. In FIG. 2, a P-type well 2, which is an anode of a photodiode, is formed on an N-type substrate 1, and an N-type region 3, which is a cathode of a photodiode and also a source of a MOS transistor, and a MOS l are formed thereon. -Rangista fin. N-type region 4 which is in
is formed.
Ｎ型領域３およσ４の間の領域上にはゲート５が設けら
れ、まｌＣ隣接する画素との分離のため、酸化ＩＩ！ｉ
！６が形成される。さらに、Ｎ型領域３下の一部分に高
１度Ｐ型領域７が形成される。A gate 5 is provided on the region between the N-type region 3 and σ4, and is oxidized II! for isolation from adjacent pixels. i
! 6 is formed. Furthermore, a high 1 degree P type region 7 is formed in a portion below the N type region 3.
次に、第２図に示す従来の固体搬像装置の動作について
説明する。Ｐ型ウェル２〈アノード）とＮ型領域３（カ
ソード）とから構成されるフォトタイオード２に光が入
射すると、光電流が発生し、ＰＮ接合領域に蓄積される
。そして、信号読出し時には、Ｎ型領域３（ソース）、
ゲート５ ａ３よびＮ型領域４（ドレイン）からなるＭ
ＯＳトランジスタがオンし、ソースからドレインへ光信
号量に相当する電流が流れ、ドレイン４から信号が取出
される。Next, the operation of the conventional solid-state imager shown in FIG. 2 will be explained. When light enters the photodiode 2, which is composed of a P-type well 2 (anode) and an N-type region 3 (cathode), a photocurrent is generated and accumulated in the PN junction region. At the time of signal reading, N type region 3 (source),
M consisting of gate 5 a3 and N type region 4 (drain)
The OS transistor is turned on, a current corresponding to the amount of optical signal flows from the source to the drain, and a signal is extracted from the drain 4.
ところで上述のように構成された従来の固体撮像装置に
ｄ３いて、光に対する高い感度をもつためには、広い面
積のフ第１・ダーイオードあるいは低い濃度のＩＤ型ウ
ェル２が必要である。しかし一方、信号の飽和信号レベ
ル（ダイナミックレンジ）を増大するためにはフ第１・
ダイオードの面積を広くするか、またはＰ型ウェル２の
濃度を増大することが必要である。以上の要求に応える
ため、通常はフォトダイオードのＮ型領域３下のＰ型ウ
ェル２の一部に、高濃度Ｐ型領域７を設置ノ、Ｐ壁領域
濃度の最適化を行なって、光に対する高い感度とダイナ
ミックレンジの増大とを同時に図２っている。By the way, in order to have high sensitivity to light in the conventional solid-state imaging device d3 constructed as described above, a wide-area first diode or a low-concentration ID type well 2 is required. However, on the other hand, in order to increase the saturation signal level (dynamic range) of the signal,
It is necessary to increase the area of the diode or increase the concentration of the P-type well 2. In order to meet the above requirements, a high-concentration P-type region 7 is usually installed in a part of the P-type well 2 under the N-type region 3 of the photodiode, and the concentration of the P-wall region is optimized. Figure 2 shows high sensitivity and increased dynamic range at the same time.
しかしながら、解像度の向上のため、個々の画素、すな
わちフ第１〜ダイΔ−ドの面積を小さくした場合、上述
のように、高感度とダイナミックレンジの増大とを同時
に実現することは困難になる。However, if the area of each pixel, that is, the area of the first to die Δ-des, is reduced in order to improve the resolution, it becomes difficult to simultaneously achieve high sensitivity and an increase in the dynamic range as described above. .
上述の欠点を解消するために、フォトダイオードに代え
てフォトトランジスタを用いる方法が考えられる。In order to eliminate the above-mentioned drawbacks, a method of using a phototransistor instead of a photodiode can be considered.
第３図は、第２図のフォトダイオードに代えて、フォト
トランジスタを用いた例の模式的断面図であり、第２図
に比較して、ＭＯＳトランジスタのソースであり、フォ
トトランジスタのコレクタでもあるＮ型領域３と分離用
酸化膜６との間に、フォトトランジスタのエミッタとな
るＮ型領域８が設けられている点で異なっている。この
場合、フォトトランジスタの電流増幅率をｈＦＥとする
と、光電流のｈＦＥ倍の信号電流が得られ、小さな面積
でも必要な感度を得ることが可能である。FIG. 3 is a schematic cross-sectional view of an example in which a phototransistor is used instead of the photodiode in FIG. The difference is that an N-type region 8, which becomes the emitter of the phototransistor, is provided between the N-type region 3 and the isolation oxide film 6. In this case, if the current amplification factor of the phototransistor is hFE, a signal current that is hFE times the photocurrent can be obtained, and it is possible to obtain the necessary sensitivity even with a small area.
しかしながら、ＭＯＳ ｔ−ランジスタのしきい値およ
びフォトトランジスタの電流増幅率ｈｒｓの安定化のた
めには、高濃度Ｐ型鋼域７は、コレクタかつソースであ
るＮ型領域３に対して余裕をもって小さく作る必要があ
る一方、期待される信号飽和レベルすなわち飽和信号電
荷の増大のためには、高濃度Ｐ型鋼域はある程度の大き
さを確保した高濃度領域における接合リーク電流の増大
と雑音の影響を取り除かなければならず、したがって画
素の微細化は困難である。However, in order to stabilize the threshold value of the MOS t-transistor and the current amplification factor hrs of the phototransistor, the high-concentration P-type steel region 7 must be made small enough with respect to the N-type region 3, which is the collector and source. On the other hand, in order to increase the expected signal saturation level, that is, the saturation signal charge, the high concentration P-type steel area must be large enough to eliminate the increase in junction leakage current and the effects of noise in the high concentration area. Therefore, it is difficult to miniaturize pixels.
［発明の概要］
それゆえに、この発明の目的は、上述の欠点を解消し、
高感度を維持しながら飽和信号のレベルの増大を図り、
同時に高集積化を可能にした固体撮像装置を提供するこ
とである。[Summary of the invention] Therefore, the object of the invention is to overcome the above-mentioned drawbacks and to
Increasing the saturation signal level while maintaining high sensitivity,
At the same time, it is an object of the present invention to provide a solid-state imaging device that enables high integration.
この発明は、要約すれば、従来のＰＮ接合による接合容
量に並列に新たにＭＩＳｌｆｌ造による容量を付加する
ことによって蓄積される電荷量を増大し、それによって
飽和信号レベルを増大し、併せて高集積化が可能なよう
に構成したものである。In summary, this invention increases the amount of charge stored by adding a new capacitance made by MISlfl in parallel to the junction capacitance made by the conventional PN junction, thereby increasing the saturation signal level and increasing the saturation signal level. The structure is such that it can be integrated.
この発明の上述の目的およびその他の目的と特徴は以下
に図面を参照して行なう詳細な説明から一層明らかとな
ろう。The above objects and other objects and features of the present invention will become more apparent from the detailed description given below with reference to the drawings.
［発明の実施例コ
第４図はこの発明の一実施例を示す模式的断面図である
。第４図に示す例は、以下の点を除いて前述の第３図に
示した例と同じである。すなわち、Ｎ型領域３上に絶縁
膜１０が形成され、さらにその上にポリシリコンからな
る電極９が設けられている。Embodiment of the Invention FIG. 4 is a schematic sectional view showing an embodiment of the invention. The example shown in FIG. 4 is the same as the example shown in FIG. 3 above, except for the following points. That is, an insulating film 10 is formed on the N-type region 3, and an electrode 9 made of polysilicon is further provided thereon.
次に、第４図に示す実施例の動作について説明する。光
が照射されると、フォトトランジスタに光電流が発生し
、その信号電荷はフォトトランジスタのコレクタであり
、ＭＯＳ ｔ−ランジスタのソースであるＮ型領域３に
蓄積される。第３図の従来例では、この信号電荷はＮ型
領ｈｉ！３とＰ型ウェル２との間に形成されるＰＮ接合
容量のみで蓄積されるが、この第４図の実施例では、Ｎ
型領域３とＮ型領域３の少なくとも一部を−覆って形成
された絶縁膜１０と電極９とによって新たにＭＩＳ構造
による容量が形成され、上述のＰＮ接合容量に並列に接
続された形になるので、飽和信号電荷量。Next, the operation of the embodiment shown in FIG. 4 will be explained. When irradiated with light, a photocurrent is generated in the phototransistor, and the signal charge is accumulated in the N-type region 3, which is the collector of the phototransistor and the source of the MOS t-transistor. In the conventional example shown in FIG. 3, this signal charge is in the N-type region hi! 3 and the P-type well 2, but in the embodiment shown in FIG.
A new MIS structure capacitor is formed by the insulating film 10 and the electrode 9, which are formed to cover at least part of the type region 3 and the N-type region 3, and is connected in parallel to the above-mentioned PN junction capacitor. Therefore, the saturation signal charge amount.
が増大し、かつ画素の大きさを増大する必要がない。す
なわち、ＭＩＳ構造の電極９は直流的に一定であれば問
題はなく、たとえば、絶縁ｌ１１１１０が５００オング
ストロームの二酸化珪素であれば、ＰＮ接合に蓄え得る
以上の電荷を蓄積することができ、また、絶縁ｍ１０に
窒化シリコン脇を使用すれば、さらに大きな容量を得る
ことができる。increases, and there is no need to increase the pixel size. That is, there is no problem as long as the electrode 9 of the MIS structure has a constant direct current. For example, if the insulation l11110 is made of 500 angstrom silicon dioxide, it is possible to store more charge than can be stored in the PN junction, and If a silicon nitride layer is used for the insulation m10, an even larger capacity can be obtained.
なお、実施例では、電極９としてポリシリコンを用いた
ＭＩＳ構造の例を示したが、電極材料としては、導電性
を有するものであれば、どのような材質であろうと使用
できることは明白である。In addition, in the example, an example of a MIS structure using polysilicon as the electrode 9 was shown, but it is clear that any material can be used as the electrode material as long as it has conductivity. .
また、この実施例では、フォトトランジスタをＮＰＮ型
のトランジスとしたが、ＰＮＰ型の１〜ランジスタであ
っても同様の効果が得られる。Further, in this embodiment, the phototransistor is an NPN type transistor, but the same effect can be obtained even if it is a PNP type transistor.
［発明の効果］
以上のように、この発明では、フォトトランジスタのコ
レクタでありかつＭＯＳ ｔ−ランジスタのソースであ
る領域上の少なくとも一部を覆って絶縁膜と電極とを形
成し、従来のＰＮ接合容量と並列の関係になるＭＩＳ構
造の容量を形成するように構成したので、集積度を犠牲
にせず、飽和信号電荷量すなわち飽和信号レベルを増大
することができる。[Effects of the Invention] As described above, in the present invention, an insulating film and an electrode are formed covering at least a part of the region that is the collector of the phototransistor and the source of the MOS t-transistor, and Since the capacitor of the MIS structure is formed in a parallel relationship with the junction capacitor, the saturation signal charge amount, that is, the saturation signal level can be increased without sacrificing the degree of integration.
第１図は従来のＭＯ３Ｏ３形１１ｔ （ｉ装置の一例の
等価回路図である。第２図は従来のＭＯ８形固体撮像装
置の模式的断面図である。第３図は従来のフォトトラン
ジスタを用いたＭＯ８形固体ｍ像装置の模式的断面図で
ある。第４図はこの発明の一実施例を示す模式的断面図
である。
図において、１はＮ型基板、２はＰ型ウェル、３．４．
８はＮ型領域、５はゲート、６は分離用酸化膜、７は高
Ｓ度Ｐ型領域、９は電極、１０は絶縁膜、１１はフォト
ダイオード、１２はフォトダイオードの容量、１３はＭ
ＯＳ ｌ−ランジスタを示す。
代 理 人 大 岩 増 雄
第１ 口
第２１〉１
第３１＝Ｔ
第４１７
１ンFig. 1 is an equivalent circuit diagram of an example of a conventional MO3O3 type 11t (i device). Fig. 2 is a schematic cross-sectional view of a conventional MO8 type solid-state imaging device. Fig. 3 is a diagram using a conventional phototransistor. FIG. 4 is a schematic cross-sectional view showing an embodiment of the present invention. In the figure, 1 is an N-type substrate, 2 is a P-type well, and 3 .4.
8 is an N-type region, 5 is a gate, 6 is an isolation oxide film, 7 is a high S degree P-type region, 9 is an electrode, 10 is an insulating film, 11 is a photodiode, 12 is a capacitance of the photodiode, 13 is M
OS l-transistor is shown. Agent Masu Oiwa 1st mouth 21〉1 31st=T 417th 1st
Claims (3)
電形とは逆導電形の第１の拡散領域が形成され、前記第
１の拡散領域中に、前記第１の導電形の第２の拡ｗｉ層
と、第３の拡散層ど、第４０）拡散層とが形成され、前
記第２の拡散層はＭ ＯＳｌ−ランジスタのドレインで
あり、前記第３の拡散層は〜４０ Ｓ ｔ−ランジスタ
のソースＣあり、前記第４の拡散層は前記第３の拡散層
に隣接し、フォトトランジスタのエミッタである固体Ｒ
象装置であって、 前記第３の拡散層上の少なくとも一部分を覆って絶縁膜
どさらにその上に電極配線とを形成することにより、前
記第３の拡散層上にＭＩＳ構造を形成し１＝ことを特徴
とする、固体撮像装置。(1) A first diffusion region of a conductivity type opposite to the first conductivity type is formed on a semiconductor substrate of a first conductivity type, and a first diffusion region of a conductivity type opposite to the first conductivity type is formed in the first diffusion region. a second diffusion layer, a third diffusion layer, etc., are formed, the second diffusion layer is the drain of the MOSI transistor, and the third diffusion layer is the drain of the MOS transistor. 40 S t-There is a source C of the transistor, the fourth diffusion layer is adjacent to the third diffusion layer, and a solid R is the emitter of the phototransistor.
an MIS structure is formed on the third diffusion layer by forming an insulating film covering at least a portion of the third diffusion layer and an electrode wiring thereon; A solid-state imaging device characterized by:
ン窒化膜と二酸化珪素との多層膜である、特許請求の範
囲第１項記載の固体撮像装置。(2) The solid-state imaging device according to claim 1, wherein the insulating film is a silicon nitride film or a multilayer film of a silicon nitride film and silicon dioxide.
請求の範囲第１項記載の固体撮像装置。(3) In the solid-state imaging device according to claim 1, the insulating film is a tantalum oxide film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58151896A JPS6042988A (en) | 1983-08-18 | 1983-08-18 | Solid-state image pickup device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58151896A JPS6042988A (en) | 1983-08-18 | 1983-08-18 | Solid-state image pickup device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6042988A true JPS6042988A (en) | 1985-03-07 |
Family
ID=15528557
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58151896A Pending JPS6042988A (en) | 1983-08-18 | 1983-08-18 | Solid-state image pickup device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6042988A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0295365A2 (en) * | 1987-05-11 | 1988-12-21 | Messerschmitt-Bölkow-Blohm Gesellschaft mit beschränkter Haftung | Semiconductor device with capacitive read out of the charge carriers and having an integrated bias supply |
-
1983
- 1983-08-18 JP JP58151896A patent/JPS6042988A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0295365A2 (en) * | 1987-05-11 | 1988-12-21 | Messerschmitt-Bölkow-Blohm Gesellschaft mit beschränkter Haftung | Semiconductor device with capacitive read out of the charge carriers and having an integrated bias supply |
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