JPS61115356A - Photodetecting element - Google Patents
Photodetecting elementInfo
- Publication number
- JPS61115356A JPS61115356A JP59237347A JP23734784A JPS61115356A JP S61115356 A JPS61115356 A JP S61115356A JP 59237347 A JP59237347 A JP 59237347A JP 23734784 A JP23734784 A JP 23734784A JP S61115356 A JPS61115356 A JP S61115356A
- Authority
- JP
- Japan
- Prior art keywords
- semiconductor
- energy band
- band width
- layer
- thickness
- 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
- 239000004065 semiconductor Substances 0.000 claims abstract description 88
- 238000010030 laminating Methods 0.000 claims abstract description 4
- 239000012535 impurity Substances 0.000 claims description 24
- 239000000969 carrier Substances 0.000 claims description 10
- 238000009792 diffusion process Methods 0.000 claims description 4
- 230000001443 photoexcitation Effects 0.000 claims 1
- 239000013078 crystal Substances 0.000 abstract description 13
- 230000035945 sensitivity Effects 0.000 abstract description 6
- 239000000758 substrate Substances 0.000 abstract description 5
- 229910002665 PbTe Inorganic materials 0.000 abstract description 4
- OCGWQDWYSQAFTO-UHFFFAOYSA-N tellanylidenelead Chemical compound [Pb]=[Te] OCGWQDWYSQAFTO-UHFFFAOYSA-N 0.000 abstract description 4
- 229910001632 barium fluoride Inorganic materials 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 5
- 230000005684 electric field Effects 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 238000010587 phase diagram Methods 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 2
- 229910052745 lead Inorganic materials 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- -1 Pb Te Substances 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000002772 conduction electron Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 229910052714 tellurium Inorganic materials 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
-
- 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
- H01L31/0248—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 characterised by their semiconductor bodies
- H01L31/0352—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 characterised by their semiconductor bodies characterised by their shape or by the shapes, relative sizes or disposition of the semiconductor regions
- H01L31/035236—Superlattices; Multiple quantum well structures
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Nanotechnology (AREA)
- Life Sciences & Earth Sciences (AREA)
- Optics & Photonics (AREA)
- Crystallography & Structural Chemistry (AREA)
- Biophysics (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
- Light Receiving Elements (AREA)
Abstract
Description
【発明の詳細な説明】
（産業上の利用分野）
本発明はエネルギーバンド幅の大きい半導体とそれの小
さい半導体を超格子構造に積層して構成した光検出素子
に関する。DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a photodetector element constructed by laminating a semiconductor with a large energy band width and a semiconductor with a small energy band width in a superlattice structure.
前記構造により暗抵抗の高い、暗電流の小さい高感度高
速応答の光検出素子が得られる。With the above structure, a photodetecting element with high dark resistance, low dark current, and high sensitivity and high speed response can be obtained.
（従来の技術）
従来の光導電形の光検出素子を第３〜５図を参照して説
明する。(Prior Art) A conventional photoconductive type photodetecting element will be explained with reference to FIGS. 3 to 5.
第３図は従来の光導電形の光検出素子の構成例を示す断
面図である。FIG. 3 is a sectional view showing an example of the configuration of a conventional photoconductive type photodetecting element.
半導体１）内には入射窓１７を介して入射した入射光１
８によって電子−正孔対が生成される。Incident light 1 enters the semiconductor 1) through the entrance window 17.
8 generates electron-hole pairs.
電極パット１２・１２は前記半導体１）内のキャリア（
電子と正孔）を収集する電極パットで前記半導体１）の
表面両側に設けられている。The electrode pads 12, 12 are carriers (
Electrode pads for collecting electrons and holes are provided on both sides of the surface of the semiconductor 1).
電極パット１２・１２はリードワイヤ１３・１３によっ
て金属ステム１５内にハーメチックシール１９・１９を
介して支持されている電極に接続されている。The electrode pads 12, 12 are connected by lead wires 13, 13 to electrodes supported within the metal stem 15 via hermetic seals 19, 19.
これら電極間に外部から電圧を印加することによって、
当該半導体１）中に生じた電子あるいは正孔は各電極１
２・１２に走行し、入射光１８に応・じた信号電流とし
て取り出される。By applying an external voltage between these electrodes,
Electrons or holes generated in the semiconductor 1) are transferred to each electrode 1.
2.12, and is taken out as a signal current according to the incident light 18.
なお図において１４は絶縁体で金属ステム１５と半導体
１）との電気的分離をしている。１６はステム１５のキ
ャンプである。In the figure, 14 is an insulator that electrically isolates the metal stem 15 and the semiconductor 1). 16 is the camp of stem 15.
次に前記半導体光検出器の動作を第４図および第５図を
参照して説明する。Next, the operation of the semiconductor photodetector will be explained with reference to FIGS. 4 and 5.
第４図は真性半導体を光導電形光検出素子として使用し
たときのバンド構造を示す略図である。FIG. 4 is a schematic diagram showing a band structure when an intrinsic semiconductor is used as a photoconductive type photodetecting element.
この種の光検出素子用の半導体では不純物を可能な限り
少なくしており、半導体の化学的ポテンシャルであるフ
ェルミレベルは、当該半導体のエネルギーバンド幅Ｅｇ
の中央付近になっている。In semiconductors for this type of photodetector, impurities are kept as low as possible, and the Fermi level, which is the chemical potential of the semiconductor, is the energy band width Eg of the semiconductor.
It is near the center of.
エネルギーバンド幅Ｅｇより大なるエネルギーをもつ光
の入射によって半導体中で励起された電子−正孔対は外
部から印加された電界に沿って走行し電極から信号電流
として得られる。Electron-hole pairs excited in the semiconductor by the incidence of light having an energy greater than the energy band width Eg travel along an externally applied electric field and are obtained as a signal current from the electrode.
第５図は外因性の不純物レベルを導入する光導電形半導
体光検出素子のバンド構造を示す略図である。FIG. 5 is a schematic diagram illustrating the band structure of a photoconductive semiconductor photodetector device incorporating extrinsic impurity levels.
ドナーレベルと伝導帯の底の間のエネルギー幅Ｅ ｇｆ
が光検出の限界波長である。このエネルギーより大なる
光の入射で励起された伝導帯内の電子は外部回路が供給
する電界に沿って走行し光信号として取り出される。Energy width E gf between the donor level and the bottom of the conduction band
is the critical wavelength for photodetection. Electrons in the conduction band excited by the incident light with energy greater than this travel along an electric field supplied by an external circuit and are extracted as an optical signal.
前記第４図に示す、バンド構造の光検出素子を得るため
には、不純物の混入しない真性半導体を製造することが
必要である。不純物の混入しない真性半導体を製造する
ためには、不純物除去のために高度の技術が要求される
。In order to obtain the photodetecting element with the band structure shown in FIG. 4, it is necessary to manufacture an intrinsic semiconductor that is free from impurities. In order to manufacture an intrinsic semiconductor free of impurities, advanced technology is required to remove impurities.
この技術はよく発展したシリコンプロセス技術において
も困難さがあり、特にエネルギーバンド幅の小さい■−
■族あるいはＩＶ−Ｖｌ族あるいは■−■族化合物半導
体においては、非常に高度な技術となる。This technology is difficult even with well-developed silicon process technology, especially the narrow energy bandwidth.
This is a very advanced technology for group (1), IV-Vl, or (2)-(2) group compound semiconductors.
また相図の上からＩＶ−Ｖｌ族化合物半導体例えばＰｂ
Ｔｅ、あるいはＰ ｂ＋−Ｌｓ ｎｚ Ｔ ｅ等では理
論的にも真性半導体とはなり得ない。Also, from the top of the phase diagram, IV-Vl group compound semiconductors such as Pb
Te, Pb+-LsnzTe, etc. cannot theoretically become an intrinsic semiconductor.
したがって、通常はどうしてもフェルミレベルがエネル
ギーバンド幅の中央付近からずれた状態で製作されるこ
とになる。Therefore, normally the device is manufactured with the Fermi level deviating from around the center of the energy band width.
このために熱励起された電子あるいは正孔が、光入射の
ない状態にも存在することになり、暗電流が大きくなり
暗抵抗も小さいという好ましくない特性が現れる。For this reason, thermally excited electrons or holes exist even in a state where no light is incident, resulting in unfavorable characteristics such as increased dark current and decreased dark resistance.
この光検出素子のＳ／Ｎは光入射時の光励起された電子
−正孔対数と暗状態との比から与えられるが、エネルギ
ーバンド幅の小さい赤外線検出素子の場合、特にこのＳ
／Ｎを大きくすることができないという問題がある。The S/N of this photodetecting element is given by the ratio of the photoexcited electron-hole logarithm at the time of light incidence and the dark state.
There is a problem that /N cannot be increased.
さらに第５図の場合には第４図の真性半導体とは逆に不
純物を導入し、不純物準位に電子をつめておくことにな
る。Furthermore, in the case of FIG. 5, impurities are introduced contrary to the intrinsic semiconductor shown in FIG. 4, and electrons are packed in the impurity level.
このとき禁止帯中に不純物準位を形成する場合には、こ
の不純物濃度を十分大きくすることができるかが感度を
決定する。しかし、この不純物準位の状態密度は価電子
帯、伝導帯のそれとは比較にならない程小さいので感度
が小さいという欠点がある。If an impurity level is formed in the forbidden band at this time, sensitivity is determined by whether the impurity concentration can be made sufficiently large. However, the density of states of this impurity level is much smaller than that of the valence band and conduction band, so it has the disadvantage of low sensitivity.
また不純物濃度を大きくするとホッピング伝導あるいは
不純物準位での伝導が生じ、暗抵抗が低く、暗電流が大
きくなるという問題も生じる。Furthermore, when the impurity concentration is increased, hopping conduction or conduction at the impurity level occurs, resulting in problems such as low dark resistance and large dark current.
（発明の目的）
本発明の目的は単一半導体では得ることができない、暗
抵抗が大きくかつ高感度の光検出素子を提供することに
ある。(Objective of the Invention) An object of the present invention is to provide a photodetecting element with high dark resistance and high sensitivity, which cannot be obtained with a single semiconductor.
（発明の構成）
前記目的を達成するために、本発明による光検出素子は
、エネルギーバンド幅の大きい半導体とそれの小さい半
導体を超格子構造にａ層して構成されている。(Structure of the Invention) In order to achieve the above-mentioned object, a photodetecting element according to the present invention is constructed by forming a layer A of a semiconductor having a large energy band width and a semiconductor having a small energy band width in a superlattice structure.
（実施例）
以下、図面等を参照して本発明をさらに詳しく説明する
。(Example) Hereinafter, the present invention will be described in more detail with reference to the drawings and the like.
第１図は本発明による光検出素子の実施例を示す断面図
である。FIG. 1 is a sectional view showing an embodiment of a photodetecting element according to the present invention.
この実施例は、赤外線域の光検出器の半導体としてＰｂ
ＴｅとＰｂＯ，８ＳｎＯ，２Ｔｅの２種の半導体で超格
子積層形構造の素子を形成したものである。In this example, Pb is used as a semiconductor for a photodetector in the infrared region.
An element with a superlattice stacked structure is formed using two types of semiconductors: Te, PbO, 8SnO, and 2Te.
基板１として、蒸着される半導体結晶の格子定数とほぼ
一致する格子定数をもち、かつ熱膨張係数も互いに殆ど
等しい結晶を用いる。As the substrate 1, a crystal is used which has a lattice constant that almost matches that of the semiconductor crystal to be deposited, and whose thermal expansion coefficients are also almost the same.
この実施例では、ＢａＦ２の（１）１）結晶面を使用し
ている。ＫＣＩ、ＮａＣ１の（１００）結晶面等を用い
てもよい。In this example, the (1)1) crystal plane of BaF2 is used. The (100) crystal plane of KCI, NaCl, etc. may be used.
エネルギーバンド幅の大きい半導体として、この実施例
では室温でエネルギーバンド幅０．２９ ｅ Ｖをもつ
ＰｂＴｅを用いる。In this embodiment, PbTe, which has an energy band width of 0.29 eV at room temperature, is used as a semiconductor with a large energy band width.
エネルギーバンド幅の大きい半導体の第１層２−１を４
〜５μｍ厚に基板上に蒸着する。この膜厚は本素子を基
板１に緊密に保持させるために必要な厚さである。The first layer 2-1 of a semiconductor with a large energy band width is
Deposit on the substrate to a thickness of ~5 μm. This film thickness is necessary for tightly holding this element to the substrate 1.
このとき蒸着速度を制御してＰ形結晶で大略２Ｘ１０１
８ｅ１ｍ−’の不純物濃度とする。At this time, by controlling the deposition rate, approximately 2×101
The impurity concentration is 8e1m-'.
エネルギーバンド幅の小さい半導体として、この実施例
ではエネルギーバンド幅が室温で０．２１ ｅｖＴｈｐ
ｂＯ，８ＳｎＯ，２Ｔｅを用いる。As a semiconductor with a small energy band width, this example has an energy band width of 0.21 evThp at room temperature.
bO, 8SnO, and 2Te are used.
エネルギーバンド幅の小さい半導体の第１層３−１を５
００人の厚さに蒸着して形成する。The first layer 3-1 of a semiconductor with a small energy band width is
It is formed by vapor deposition to a thickness of 0.00 mm.
このとき本半導体の構成元素であるＴｏの蒸気圧制御で
ｎ形半導体で大略ｌＸｌ０”ｅｌｍ−３の不純物濃度と
する。At this time, by controlling the vapor pressure of To, which is a constituent element of the present semiconductor, the impurity concentration is set to approximately 1X10"elm-3 in an n-type semiconductor.
さらに前記エネルギーバンド幅の小さい半導体の第１層
３−１の上に前記エネルギーバンド幅の大きい半導体の
第２層２−２（膜厚５００人）を前述のようにして形成
する。Furthermore, on the first layer 3-1 of the semiconductor with a small energy band width, the second layer 2-2 (thickness: 500 layers) of the semiconductor with a large energy band width is formed as described above.
次に前記エネルギーバンド幅の大きい半導体の第２ｔｉ
２−２の上にエネルギーバンド幅の小さい半導体の第２
層３−２を５００人の厚さでというようにして次々に、
５００人の厚さで各３０層、２−３０から３−３０まで
を形成する。そして最後にエネルギーバンド幅の大きい
半導体の第３１層２−３１を４〜５μｍの厚さに蒸着す
る。Next, the second ti of the semiconductor with a large energy band width is
A second semiconductor with a narrow energy band width is added on top of 2-2.
Layer 3-2 is 500 people thick, and so on, one after another.
Form 30 layers each, from 2-30 to 3-30, with a thickness of 500 people. Finally, a 31st layer 2-31 of a semiconductor having a large energy band width is deposited to a thickness of 4 to 5 μm.
前述した各半導体層の特性を要約して回連する。The characteristics of each semiconductor layer described above will be summarized and repeated.
○エネルギーバンド幅の大きい半導体層（２−１〜２−
３１）
エネルギーバンド幅： ０．２９ ｅ Ｖ不純物濃度
、： ２Ｘ１０” ａｍ−３導電形
：ｐ形
Ｏエネルギーバンド幅の小さい半導体層（３−１〜３−
３０）
エネルギーバンド幅：０．２１ｅＶ
不純物濃度 ’ｌＸｌ０１７Ｃ１）１−３導電形
Ｉｎ形
次に前述のようにして積層された素子の実装工程を説明
する。○Semiconductor layer with large energy band width (2-1 to 2-
31) Energy band width: 0.29 eV impurity concentration
,: 2X10” am-3 conductivity type
: p-type O semiconductor layer with small energy band width (3-1 to 3-
30) Energy band width: 0.21eV Impurity concentration 'lXl017C1) 1-3 Conductivity type In type Next, the mounting process of the elements stacked as described above will be explained.
積層された素子の側面をメサエッチングし容器台７に取
り付ける。The side surfaces of the stacked elements are mesa-etched and attached to the container stand 7.
エネルギーバンド幅の大きい半導体層の最上および最下
位の層２−３１と２−１にＩｎ金属４ａと４ｂを載置す
る。In metals 4a and 4b are placed on the top and bottom layers 2-31 and 2-1 of the semiconductor layer having a large energy band width.
それぞれを金線５ａと５ｂを介して各電極６ａと６ｂに
接続する。Each is connected to each electrode 6a and 6b via gold wires 5a and 5b.
なお各電極６ａと６ｂは予め容器台７にハーメチックシ
ール１０ａとｌＯｂで絶縁されて支持されている。容器
台７にキャップ８を封着する。Note that the electrodes 6a and 6b are supported in advance on the container stand 7 while being insulated by hermetic seals 10a and 1Ob. A cap 8 is sealed on a container stand 7.
前述した素子の光検出器としての動作原理を第２図を参
照して説明する。The principle of operation of the above-mentioned element as a photodetector will be explained with reference to FIG.
前記エネルギーバンド幅の大きいｎ形半導体（以下半導
体■という）の禁止帯幅をＥｇｌとし、前記エネルギー
バンド幅の小さいｎ半導体（以下半導体■という）の禁
止帯幅を８ｇ２とする。Let Egl be the bandgap of the n-type semiconductor with a large energy band width (hereinafter referred to as semiconductor 2), and let 8g2 be the bandgap of the n-type semiconductor with a small energy band width (hereinafter referred to as semiconductor 2).
この実施例の場合、ＥｇｌをもつＰｂＴｅの結晶と８ｇ
２となるＰｂＯ，８ＳｎＯ，２Ｔｅ結晶は界面でΔＥｃ
、 ΔＥＶのステップをもつ接合が形成される。In this example, PbTe crystal with Egl and 8g
2, PbO, 8SnO, 2Te crystals have ΔEc at the interface.
, a junction with steps of ΔEV is formed.
本例の場合Ｅｇ＋側の結晶は高濃度（２Ｘ１０”ｅｌｍ
−１）のＰ形となっている。In this example, the crystals on the Eg+ side have a high concentration (2X10”elm
-1) P type.
ΔＥｃ、 ΔＥｖの大きさは半導体Ｉ、Ｉｆの種類と
不純物濃度の大きさで決定される。The magnitudes of ΔEc and ΔEv are determined by the types of semiconductors I and If and the magnitude of impurity concentration.
この実施例の場合、ΔＥＣは２ＱｍｅＶ、ΔＥＶは８０
ｍｅＶとなっている。In this example, ΔEC is 2QmeV and ΔEV is 80
meV.
Ｅｇｘ側の多数キャリアである価電子帯にある正孔はよ
りエネルギー準位の低い８ｇ２側に移動し、８２２例の
電子を補償したのち８ｇ２側の価電子帯へ落ちこむ。Holes in the valence band, which are majority carriers on the Egx side, move to the 8g2 side, which has a lower energy level, and after compensating for 822 electrons, fall into the valence band on the 8g2 side.
このとき２ｇ１側から８ｇ２側へ正孔が移動し、捕獲さ
れて、フェルミレベルが半導体１，１）間で一定となり
定常状態がつくり出される。At this time, holes move from the 2g1 side to the 8g2 side and are captured, and the Fermi level becomes constant between the semiconductors 1 and 1), creating a steady state.
この積層された結晶に（８ｇ２＋ΔＥｃ）以上のエネル
ギーの光が入射すると価電子帯の電子は励起され、伝導
帯中に上がり、積層結晶に印加された電界によって、伝
導帯のこれらの励起電子は移動し信号電流となる。When light with an energy of (8g2 + ΔEc) or more is incident on this stacked crystal, electrons in the valence band are excited and rise into the conduction band, and due to the electric field applied to the stacked crystal, these excited electrons in the conduction band are moved. becomes a signal current.
積層結晶の厚さは光に対する吸収係数によって決定され
る。The thickness of the laminated crystal is determined by the absorption coefficient for light.
この実施例の場合、波長６μｍの光に対して吸収係数は
１０’Ｃｌ１−１であるから２〜３μｍが適当である。In the case of this embodiment, the absorption coefficient is 10'Cl1-1 for light with a wavelength of 6 μm, so 2 to 3 μm is appropriate.
また積層する各結晶の厚さは価電子帯の正孔の拡散移動
距離によって決定される。この実施例の場合、ＰｂＴｅ
は半導体の中でも拡散距離は大きく、５００人の膜厚が
適当である。Further, the thickness of each crystal layered is determined by the diffusion distance of holes in the valence band. For this example, PbTe
has a long diffusion distance even among semiconductors, and a film thickness of 500 people is appropriate.
三元系の化合物半導体であるＰｂ、Ｓｎ、Ｔｅは金属学
での相図の上からＴｅ蒸気圧が高いので真性半導体を実
現するのは困ｉｌ！で、１０１）０１６ｅ１まで不純物
濃度を下げることも現状では不可能である。Pb, Sn, and Te, which are ternary compound semiconductors, have a high Te vapor pressure based on the phase diagram in metallurgy, so it is difficult to realize an intrinsic semiconductor! Therefore, it is currently impossible to lower the impurity concentration to 101)016e1.
この実施例では、エネルギーバンドの大なる半導体■を
それの小さい半導体■に超格子構造で隣接することによ
って、半導体■の伝導正孔を拡散移動し、半導体■の価
電子帯に詰めることによって、多数キャリア濃度を単体
結晶のそれより下げることができる。In this example, by arranging a semiconductor (2) with a large energy band adjacent to a semiconductor (2) with a small energy band in a superlattice structure, conductive holes in the semiconductor (2) are diffused and moved and packed into the valence band of the semiconductor (2). The majority carrier concentration can be lower than that of a single crystal.
したがって、製造容易な不純物濃度の半導体でありなが
ら、上述の構造とすることで非常に製造困難な、あるい
は相図の上からはでき得ない不純物濃度を得ることがで
きる。Therefore, although it is a semiconductor with an impurity concentration that is easy to manufacture, by using the above structure, it is possible to obtain an impurity concentration that is extremely difficult to manufacture or that cannot be achieved from the phase diagram.
（変形例）
以上詳しく説明した実施例につき本発明の範囲内で種々
の変形を施すことができる。(Modifications) Various modifications can be made to the embodiments described in detail above within the scope of the present invention.
実施例での半導体■、■の伝導形をｎ、ｐにそれぞれ替
えても伝導電子の移動によって上述の結果と同一の動作
原理により光検出器となることはもちろんである。Of course, even if the conduction types of the semiconductors (1) and (2) in the embodiment are changed to n and p, respectively, a photodetector can be obtained based on the same operating principle as described above due to the movement of conduction electrons.
実施例の他にも製法上、不純物濃度が高くなる半導体あ
るいは三元系化合物半導体で超格子構造にできるＧａＡ
ｓ−ＧａＰ、ＧａＡｊ２Ａｓ−ＩｎＧａＰ、Ｉｎ５ｂ−
１ｎＡｓ等についても同様にして製作できる。In addition to the examples, GaA, which can be made into a superlattice structure using a semiconductor with a high impurity concentration or a ternary compound semiconductor due to the manufacturing method, is also available.
s-GaP, GaAj2As-InGaP, In5b-
1nAs etc. can also be manufactured in the same manner.
また前記実施例は光導電性を持つものについて詳しく説
明したが、光起電性の光検出素子にも応用可能である。Further, although the above embodiments have been described in detail with respect to photoconductive elements, it is also applicable to photovoltaic photodetecting elements.
（発明の効果）
この発明によれば、ハンド幅の大きい半導体の多数キャ
リアが拡散移動し、バンド幅の小さい半導体のバンドの
井戸中に閉じ込めることができる。(Effects of the Invention) According to the present invention, majority carriers in a semiconductor with a large band width can diffuse and move and be confined in a well in a band of a semiconductor with a small band width.
このため、バンド幅の大きい半導体の不純物濃度は、従
来技術でできるものより低くなり比抵抗は大きくなる。For this reason, the impurity concentration of the semiconductor with a large band width is lower than that which can be achieved with the conventional technology, and the resistivity becomes large.
したがって暗抵抗の大きい、暗電流の小さい素子とする
ことができる。Therefore, an element with high dark resistance and low dark current can be obtained.
また光検出感度はバンド幅の大きい半導体（Ｅｇｔ ）
と小さい半導体（Ｅｇ２）との接合バリヤ（ΔＥｃ）と
（Ｅｇｔ）との和より大きい光で励起された小数キャリ
アが印加された電界によって信号電流として得られる。In addition, the photodetection sensitivity is achieved using a semiconductor with a large bandwidth (Egt).
Minority carriers excited by the light, which is larger than the sum of the junction barrier (ΔEc) and (Egt) between the small semiconductor (Eg2) and the small semiconductor (Eg2), are obtained as a signal current by the applied electric field.
したがって従来の多数キャリアでの信号増加を比較する
より、小数キャリアの増加分は元のキャリア数との比で
は大きくなる。Therefore, compared to comparing signal increases with conventional majority carriers, the increase in minority carriers is larger in ratio to the original number of carriers.
このため高感度の検出器となる。また小数キャリアは電
界によって走行するとき障害は少なく高速でドリフトす
るので応答速度の大きい素子を実現できる。This makes it a highly sensitive detector. Furthermore, when minority carriers travel due to an electric field, they drift at high speed with few disturbances, so it is possible to realize an element with a high response speed.
６μｍの入射光に対する従来のＧｅ（Ａｕドープ）の光
検出素子のディチクティビイティ （Ｄ＊）はＩ Ｘ
１０ ” ｃｍＨＺ１）２／ Ｗである。The detictivity (D*) of a conventional Ge (Au-doped) photodetector element for an incident light of 6 μm is I
10” cmHZ1)2/W.
この実施例の場合では６μｍの入射光に対するそれは４
Ｘ １０ ” ｃ＋ｓＨＺＩ／２／Ｗが得られる。In this example, for an incident light of 6 μm, it is 4
X 10 ”c+sHZI/2/W is obtained.
また暗電流は前記従来のＧｅの光検出素子のそれの１／
１０の１〜３ｎＡである。In addition, the dark current is 1/1 that of the conventional Ge photodetector.
1-3 nA of 10.
第１図は本発明による光検出素子の実施例を示す断面図
である。
第２図は前記実施例のバンド構造を示す略図である。
第３図は従来の光導電形の光検出素子の構成例を示す断
面図である。
第４図は真性半導体を光導電形光検出素子として使用し
たときのバンド構造を示す略図である。
第５図は外因性の不純物レベルを導入する光導電形半導
体光検出素子のバンド構造を示す略図である。
１・・・基板
２−１．２−２．２−３〜２−３１
・・・エネルギーバンド幅の大きい半導体層３−１．
３−２． ３−３〜３−３０・・・エネルギーバンド幅
の小さい半導体層４ａ、４ｂ”−Ｉｎ金属
５ａ、５ｂ・・・金線
５ａ、５ｂ・・・電極
７・・・容器台
８・・・キャップ
１０ ａ、 １０ ｂ−ｔｚ−メチツクシール特許出
願人 浜松ホトニクス株式会社
代理人 弁理士 井 ノ ロ 毒
牙１ｍ
ソ
才２図
才３ｍ
才４図 才５図FIG. 1 is a sectional view showing an embodiment of a photodetecting element according to the present invention. FIG. 2 is a schematic diagram showing the band structure of the embodiment. FIG. 3 is a sectional view showing an example of the configuration of a conventional photoconductive type photodetecting element. FIG. 4 is a schematic diagram showing a band structure when an intrinsic semiconductor is used as a photoconductive type photodetecting element. FIG. 5 is a schematic diagram illustrating the band structure of a photoconductive semiconductor photodetector device incorporating extrinsic impurity levels. 1... Substrate 2-1.2-2.2-3 to 2-31... Semiconductor layer 3-1 with a large energy band width.
3-2. 3-3 to 3-30... Semiconductor layer 4a, 4b'' with small energy band width - In metal 5a, 5b... Gold wire 5a, 5b... Electrode 7... Container stand 8... Cap 10 a, 10 b-tz-methic seal patent applicant Hamamatsu Photonics Co., Ltd. agent Patent attorney Inoro Dokuga 1m Sosai 2sai 3m Sosai 4sai sai 5s
Claims (6)
い半導体を超格子構造に積層して構成した光検出素子。(1) A photodetector element constructed by laminating a semiconductor with a large energy band width and a semiconductor with a small energy band width in a superlattice structure.
導体が検出する光波長を吸収するに最適な厚さである特
許請求の範囲第１項記載の光検出素子。(2) The photodetector element according to claim 1, wherein the total thickness of the laminated layer is an optimum thickness for absorbing the light wavelength detected by a semiconductor having a narrow energy band width.
い半導体の多数キャリアの拡散長の長さ以下である特許
請求の範囲第１項記載の光検出素子。(3) The photodetecting element according to claim 1, wherein the thickness of each of the laminated layers is equal to or less than the diffusion length of majority carriers of a semiconductor having a large energy band width.
い半導体の多数キャリアの拡散長の長さ以下とした光検
出器において、エネルギーバンド幅の大きい半導体の多
数キャリアをエネルギーバンド幅の小さい半導体のエネ
ルギーバンドの井戸中に入れるようにした特許請求の範
囲第３項記載の光検出素子。(4) In a photodetector in which the thickness of each of the laminated layers is equal to or less than the diffusion length of majority carriers in a semiconductor with a large energy band width, 4. The photodetecting element according to claim 3, wherein the photodetecting element is placed in a well of an energy band.
バンドの井戸中に入れることによって真性半導体化ある
いは低不純物濃度化されたエネルギーバンド幅の大きい
半導体中を、エネルギーバンド幅が小さい半導体部から
の光励起されたキャリアを走行させる特許請求の範囲第
４項記載の光検出素子。(5) Photoexcitation from a semiconductor part with a small energy band width is applied to a semiconductor with a large energy band width that has been made into an intrinsic semiconductor or has a low impurity concentration by placing it in the well of the energy band of a semiconductor with a small energy band width. The photodetecting element according to claim 4, in which a carrier travels.
ｅ、前記エネルギーバンド幅の小さい半導体はＰｂ０．
８Ｓｎ０．２Ｔｅである特許請求の範囲第１項記載の光
検出素子。(6) The semiconductor with a large energy band width is PbT.
e, the semiconductor with a small energy band width is Pb0.
The photodetecting element according to claim 1, which is made of 8Sn0.2Te.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59237347A JPS61115356A (en) | 1984-11-09 | 1984-11-09 | Photodetecting element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59237347A JPS61115356A (en) | 1984-11-09 | 1984-11-09 | Photodetecting element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS61115356A true JPS61115356A (en) | 1986-06-02 |
Family
ID=17014040
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59237347A Pending JPS61115356A (en) | 1984-11-09 | 1984-11-09 | Photodetecting element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61115356A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61212072A (en) * | 1985-03-18 | 1986-09-20 | Nec Corp | Semiconductor light-receiving element |
| JPS62115786A (en) * | 1985-06-14 | 1987-05-27 | アメリカン テレフオン アンド テレグラフ カムパニ− | Optical device |
| JPS6377169A (en) * | 1986-09-19 | 1988-04-07 | Nec Corp | Photoconductive light detector |
| JP2007335686A (en) * | 2006-06-15 | 2007-12-27 | National Univ Corp Shizuoka Univ | Quantum well intersubband transition device |
-
1984
- 1984-11-09 JP JP59237347A patent/JPS61115356A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61212072A (en) * | 1985-03-18 | 1986-09-20 | Nec Corp | Semiconductor light-receiving element |
| JPS62115786A (en) * | 1985-06-14 | 1987-05-27 | アメリカン テレフオン アンド テレグラフ カムパニ− | Optical device |
| JPS6377169A (en) * | 1986-09-19 | 1988-04-07 | Nec Corp | Photoconductive light detector |
| JP2007335686A (en) * | 2006-06-15 | 2007-12-27 | National Univ Corp Shizuoka Univ | Quantum well intersubband transition device |
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