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JPS61268075A - PV type infrared sensing element - Google Patents

PV type infrared sensing element

Info

Publication number
JPS61268075A
JPS61268075A JP60109429A JP10942985A JPS61268075A JP S61268075 A JPS61268075 A JP S61268075A JP 60109429 A JP60109429 A JP 60109429A JP 10942985 A JP10942985 A JP 10942985A JP S61268075 A JPS61268075 A JP S61268075A
Authority
JP
Japan
Prior art keywords
crystal layer
section
sensing element
crystal substrate
mesa
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
Application number
JP60109429A
Other languages
Japanese (ja)
Inventor
Toru Maekawa
前川　通
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Fujitsu Ltd
Original Assignee
Fujitsu Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Fujitsu Ltd filed Critical Fujitsu Ltd
Priority to JP60109429A priority Critical patent/JPS61268075A/en
Publication of JPS61268075A publication Critical patent/JPS61268075A/en
Pending legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
    • H10F30/00—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors
    • H10F30/20—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors
    • H10F30/21—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors the devices being sensitive to infrared, visible or ultraviolet radiation
    • H10F30/22—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors the devices being sensitive to infrared, visible or ultraviolet radiation the devices having only one potential barrier, e.g. photodiodes
    • H10F30/221—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors the devices being sensitive to infrared, visible or ultraviolet radiation the devices having only one potential barrier, e.g. photodiodes the potential barrier being a PN homojunction
    • H10F30/2212—Individual radiation-sensitive semiconductor devices in which radiation controls the flow of current through the devices, e.g. photodetectors the devices having potential barriers, e.g. phototransistors the devices being sensitive to infrared, visible or ultraviolet radiation the devices having only one potential barrier, e.g. photodiodes the potential barrier being a PN homojunction the devices comprising active layers made of only Group II-VI materials, e.g. HgCdTe infrared photodiodes

Landscapes

  • Light Receiving Elements (AREA)
  • Solid State Image Pick-Up Elements (AREA)

Abstract

PURPOSE:To reduce thermal noises by forming a mesa section up to a section having a large x value in the vicinity of the interface from the surface of a Hg1-xCdxTe crystal layer on a crystal substrate and shaping a P-N junction in depth, which does not reach the crystal substrate, to the mesa section and the periphery of the mesa section. CONSTITUTION:A Hg1-xCdxTe crystal layer 2 is grown on a CdTe crystal substrate 1 in an epitaxial manner. A mesa section 4 is formed through etching up to a section having a large x value in the vicinity of the interface from the surface of the Hg1-xCdxTe crystal layer 2. A P-N junction is shaped in depth, which does not reach the CdTe crystal substrate 1, to the mesa section 4 and the periphery of the mesa section. Accordingly, the flowing of surface leakage-currents can be prevented without taking a measure, such as the formation of a guard-ring, the optimization of processes or the like, thus reducing thermal noises.

Description

【発明の詳細な説明】 〔概要〕 本発明は、例えば赤外線撮像装置に用いて好適な光起電
力（ｐｈｏｔｏ　　ｖｏｌｔａｉｃ：ＰＶ）型赤外線検
知素子に於いて、ＣｄＴａ結晶基板上ニＨｇ　ｌ−Ｘ　
Ｃｄ　Ｘ　Ｔ　ｅ結晶層をエピタキシャル成長させ、そ
のＨｇ＋−ｘ　Ｃｄｇ　Ｔ’　ｅ結晶層の表面がら界面
近傍のＸ値が大きい部分に達するまでエツチングを行っ
てメサ部分を形成し、そのメサ部分及びその周辺に於い
て前記’ＣｄＴｅ結晶基板に達しない深さにｐｎ接合を
形成することに依り、ガード・リングを形成したり、或
いは、プロセス条　・件の最適化を図ることなく、表面
リーク電流が流れないようにして熱雑音を低減させるよ
うにしたものである。Detailed Description of the Invention [Summary] The present invention provides a photovoltaic (PV) type infrared sensing element suitable for use in, for example, an infrared imaging device.
A mesa portion is formed by epitaxially growing a Cd By forming a pn junction at a depth that does not reach the CdTe crystal substrate mentioned above, surface leakage current can flow without forming a guard ring or optimizing process conditions. This is to reduce thermal noise.

〔産業上の利用分野〕[Industrial application field]

本発明は、Ｈｇ　Ｉ−＊　Ｃｄ）Ｉ　Ｔ　ｅ結晶を用い
るＰＶ型型外外線検知素子改良に関する。The present invention relates to an improvement of a PV type external radiation detection element using a Hg I-*Cd) I Te crystal.

〔従来の技術〕[Conventional technology]

従来、Ｈｇ　ｒ−＊　Ｃｄｇ　Ｔ　ｅ結晶を用いたｐｖ
型赤外線検知素子では、Ｘ値が均一であるＨｇｔ−３Ｉ
ＣｄｘＴｅのエピタキシャル成長面にダイオードを形成
している。Conventionally, pv using Hgr-*CdgTe crystal
In the Hgt-3I type infrared sensing element, the X value is uniform.
A diode is formed on the epitaxial growth surface of CdxTe.

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

前記のように形成したダイオードは、その周辺に於ける
表面リーク電流の為、熱雑音が大である旨の問題がある
。The diode formed as described above has a problem in that it has large thermal noise due to surface leakage current in its periphery.

この為、ダイオードの周辺にガード・リングをを形成し
たり（前者）、プロセス条件の最適化を図る（後者）な
どの対策が考えられている。For this reason, countermeasures have been considered, such as forming a guard ring around the diode (the former) and optimizing process conditions (the latter).

然しなから、前者は電極構造が複雑であり、また、後者
はプロセス管理が困難になる旨の欠点がある。However, the former has the disadvantage that the electrode structure is complicated, and the latter has the disadvantage that process control becomes difficult.

本発明は、簡単な技術を適用することに依り、ダイオー
ドの周辺に於ける表面リーク電流を低減させ、高性能の
ｐｖ赤外線検知素子を得られるようにする。The present invention reduces the surface leakage current around the diode by applying a simple technique, making it possible to obtain a high performance PV infrared sensing element.

〔問題点を解決するための手段〕[Means for solving problems]

本発明では、例えばＣｄＴｅを基板としてエピタキシャ
ル成長させたＨ　ｇ　ｒ−ｘ　ＣｄえＴｏ結晶層がＣｄ
とＨｇの相互拡散の為、その厚さ方向に組成変動を生じ
、ＣｄＴｅ基板との界面に近い程、Ｘ値が大、即ち、エ
ネルギ・バンド・ギャップは広くなり、そして、Ｘ値が
大きいと真性キャリヤ濃度が低いことが原因となって表
面リーク電流が小さくなるので、それを利用して熱雑音
を低減させる。In the present invention, for example, a H gr-x CdeTo crystal layer epitaxially grown using CdTe as a substrate is
Due to interdiffusion of Hg and Hg, a compositional variation occurs in the thickness direction, and the closer to the interface with the CdTe substrate, the larger the X value, that is, the wider the energy band gap; The surface leakage current is reduced due to the low intrinsic carrier concentration, which is utilized to reduce thermal noise.

そこで、本発明のｐｖ型赤外線検知素子では、ＣｄＴｅ
結晶基板ｌ上にＨｇ　＋−ｘ　ＣｄＸＴ　ｅ結晶層２を
エピタキシャル成長させて、そのＨｇＩ−ｘＣｄＸＴｅ
結晶層２の表面から界面近傍のＸ値が大きい部分に達す
るまでエツチングを行ってメサ部分４を形成し、そのメ
サ部分４及びその周辺に於いて前記ＣｄＴｅ結晶基板ｌ
に達しない深さにｐｎ接合を形成するようにしている。Therefore, in the pv type infrared sensing element of the present invention, CdTe
A Hg +-x CdXTe crystal layer 2 is epitaxially grown on a crystal substrate l, and the HgI-xCdXTe
A mesa portion 4 is formed by etching from the surface of the crystal layer 2 to a portion near the interface where the X value is large.
The pn junction is formed at a depth that does not reach .

〔作用〕[Effect]

前記手段を採ることに依り、ガード・リングを形成した
り、或いは、プロセスを最適化する等の手段を講じなく
とも、表面リーク電流が流れないようにすることができ
、従って、熱雑音を低減することが可能となる。By taking the above measures, it is possible to prevent surface leakage current from flowing without forming a guard ring or optimizing the process, thereby reducing thermal noise. It becomes possible to do so.

〔実施例〕〔Example〕

第１図（Ａ）乃至（Ｄ）は本発明一実施例を製造する場
合について解説する為の工程要所に於けるｐｖ型赤外線
検知素子の要部切断側面図、第２図はＸ値分布の状態を
説明する為の線図を表している。Figures 1 (A) to (D) are cross-sectional side views of essential parts of a PV-type infrared sensing element at key points in the process to explain the manufacturing of an embodiment of the present invention, and Figure 2 is an X-value distribution. It represents a diagram for explaining the state of.

第１図（Ａ）及び第２図参照 （ａｌ　　液相エピタキシャル成長（ｌｉｑｕｉｄ　　
ｐｈａｓｅ　　ｅｐｉｔａｘ３Ｆ：ＬＰＥ）を適用する
ことに依り、ＣｄＴｅ基板１上にＨｇＩ−ｘＣ（ｌｘＴ
ｅ結晶層２を厚さ数十〔μｍ〕程度にエピタキシャル成
長させる。See Figure 1 (A) and Figure 2 (al Liquid phase epitaxial growth (liquid phase epitaxial growth)
By applying phase epitax 3F: LPE), HgI-xC (lxT
The e-crystal layer 2 is epitaxially grown to a thickness of about several tens [μm].

前記のようにして得たＨｇ、、ＣｄＸＴｅ結晶層２は、
その厚さ方向に第２図に見られるように組成変動領域３
を有している。即ち、表面からＣｄＴｅ基板１との界面
に近づ（につれ、Ｘ値が大になっている。The Hg, CdXTe crystal layer 2 obtained as described above is
As seen in Fig. 2 in the thickness direction, the composition variation region 3
have. That is, the X value increases as the distance from the surface approaches the interface with the CdTe substrate 1.

第１図（Ｂ）参照 山）　通常のフォト・リソグラフィ技術を適用すること
に依り、Ｈｇ　ｒ−ｘ　Ｃｄｘ　Ｔ　ｅ結晶層２のエツ
チングを行ってメサ部分４を形成する。(See Fig. 1(B)) The mesa portion 4 is formed by etching the Hg r-x Cdx Te crystal layer 2 by applying a normal photolithography technique.

尚、このメサ・エツチングを行う場合、エツチング・マ
スクとしては適当なレジストを、また、エッチャントと
しては例えばブロムメタノ　、−ルを適用して良く、そ
して、そのエツチングは組成変動領域３に於けるＸ値が
大である部分に充分に到達するように行うものとする。When performing this mesa etching, an appropriate resist may be used as an etching mask, and, for example, bromine methane may be used as an etchant. This shall be done in such a way as to sufficiently reach the portion where the is large.

第１図（Ｃ）参照 （０）　　イオン注入法を適用することに依り、メサ部
分４及びその周辺一部にかけてＢ＋の打ち込みを行い、
熱処理を行って深さ約１〔μｍ〕程度のｐ型不純物領域
５を形成し、ｐｎ接合ダイオードを構成する。Refer to FIG. 1(C) (0) By applying the ion implantation method, B+ is implanted into the mesa portion 4 and a part of its surrounding area.
Heat treatment is performed to form a p-type impurity region 5 with a depth of about 1 [μm], thereby forming a pn junction diode.

この場合のイオン注入の条件は、 ドーズ量：　１　ｘ　１０”　〜１０”　（ｅｌｍ−”
）加速エネルギ：　１００〜２００　（ＫｅＶ）として
良い。The conditions for ion implantation in this case are: Dose: 1 x 10” to 10” (elm-”
) Acceleration energy: 100 to 200 (KeV) may be used.

図から判るように、このｐｎ接合ダイオードは、メサ部
分４に形成されたダイオード部分６と前記メサ・エツチ
ングで露出された組成変動領域３に於けるＸ値が大きい
部分に形成されたダイオード部分７とからならている。As can be seen from the figure, this pn junction diode consists of a diode portion 6 formed in the mesa portion 4 and a diode portion 7 formed in a portion where the X value is large in the composition variation region 3 exposed by the mesa etching. It is made up of.

第１図（Ｄ）参照 （ｄ）　　化学気相堆積（ｃｈｅｍｉ　ｃ’ａ　ｌ　　
ｖａｐ。See Figure 1 (D) (d) Chemical vapor deposition
vap.

ｕｒ　　ｄｅｐｏｓｉｔｉｏｎ：ＣＶＤ）法を適用する
ことに依り、Ｓ　ｉ　Ｏ２からなる絶縁膜８を厚さ約１
〜２〔μｍ〕程度に形成する。尚、絶縁膜８としてはＺ
ｎＳを用いても良い。By applying the ur deposition (CVD) method, the insulating film 8 made of SiO2 is deposited to a thickness of approximately 1 mm.
It is formed to a thickness of about 2 [μm]. Incidentally, as the insulating film 8, Z
nS may also be used.

（１１１）　　通常のフォト・リソグラフィ技術を適用
することに依り、絶縁膜８のパターニングを行い、電極
コンタクト窓を形成する。(111) By applying ordinary photolithography technology, the insulating film 8 is patterned to form electrode contact windows.

（ｆ）　　例えば蒸着法を適用することに依り、インジ
ウム（Ｉｎ）からなる電極材料膜を形成し、例えばハイ
ブリッド型の場合、電極材料膜をパターニングしてバン
プ電極９を形成する。(f) For example, by applying a vapor deposition method, an electrode material film made of indium (In) is formed, and in the case of a hybrid type, for example, the bump electrode 9 is formed by patterning the electrode material film.

このようにして作成されたｐｖ型赤外線検知素子では、
ｐｎ接合ダイオードの周辺部分、即ち、ダイオード部分
７が組成変動領域３のＸ値が大きい部分に存在している
ので、このｐｎ接合ダイオードの表面リーク電流はプレ
ーナ型のものに比較して低減される。In the PV type infrared sensing element created in this way,
Since the peripheral portion of the pn junction diode, that is, the diode portion 7 exists in the portion of the composition variation region 3 where the X value is large, the surface leakage current of this pn junction diode is reduced compared to that of the planar type. .

第３図は本発明のＰＶ型型外外線検知素子アレイにした
場合の実施例を解説する為の要部切断側面図であり、第
１図に於いて用いた記号と同記号は同部分を表すか或い
は同じ意味を持つも・のとする。FIG. 3 is a cutaway side view of essential parts for explaining an embodiment of the PV type external ray detection element array of the present invention, and the same symbols as those used in FIG. 1 refer to the same parts. shall represent or have the same meaning.

図に於いて、ＩＲは赤外線を、また、Ｑ内に−を入れた
記号は電子を示している。In the figure, IR indicates infrared rays, and the symbol Q with a minus sign (-) indicates electrons.

この実施例に於いては、赤外線検知素子間にＸ値が大き
いＨｇ、、Ｃｄ、Ｔｅ結晶層２が存在しているのみであ
るから、その部分では赤外線は吸収されずに透過してし
まい、従って、電荷も発生しないから、隣接する赤外検
知素子に電荷が流れてクロス・トークを発生するような
虞が皆無になる。In this example, since there is only a Hg, Cd, Te crystal layer 2 with a large X value between the infrared detecting elements, infrared rays are transmitted without being absorbed in that part. Therefore, since no charges are generated, there is no possibility that charges will flow to adjacent infrared detection elements and cause cross talk.

〔発明の効果〕〔Effect of the invention〕

本発明のｐｖ型赤外線検知素子では、ＣｄＴｅ結晶基板
上にエピタキシャル成長されたＨｇｌ−ｘＣｄ、Ｔｅ結
晶層の表面から界面近傍のＸ値が大きい部分に達するま
でエツチングして形成されたメサ部分と、該メサ部分及
びその周辺に於いて前記ＣｄＴｅ結晶基板に到達しない
深さに形成されたｐｎ接合とを備えた構成を採っている
。The PV-type infrared sensing element of the present invention includes a mesa portion formed by etching from the surface of the Hgl-xCd, Te crystal layer epitaxially grown on a CdTe crystal substrate until reaching a portion with a large X value near the interface; The structure includes a mesa portion and a pn junction formed at a depth that does not reach the CdTe crystal substrate in the vicinity thereof.

このような構成になっている為、ｐｖ型赤外線検知素子
をなすダイオードの周辺部分はＨｇｌ−＊ＣｄｘＴｅ結
晶層の特にＸ値が大きい部分に存在している為、その部
分での表面リーク電流は小さく、従って、熱雑音を低減
することができる。Due to this structure, the area around the diode that forms the PV-type infrared sensing element exists in the area of the Hgl-*CdxTe crystal layer where the X value is particularly large, so the surface leakage current in that area is small, and therefore can reduce thermal noise.

【図面の簡単な説明】[Brief explanation of drawings]

第１図（Ａ）乃至（Ｄ）は本発明一実施例を製造する場
合について説明する為の工程要所に於けるｐｖ型赤外線
検知素子の要部切断側面図、第２図はＨｇ　ｒ　−ｘ　
Ｃｄ　ｘ　Ｔ　ａ結晶層に於けるＸ値分布の状態を説明
する為の線図、第３図は本発明一実施例の要部切断側面
図をそれぞれ表している。 特許出願人　　　富士通株式会社 代理人弁理士　　相　谷　昭　司 代理人弁理士　　渡　邊　弘　− （Ｂ） 第１図 （Ｃ） （Ｄ） 一実施例の製造工程を説明する為の 要部切断側面図 第１図FIGS. 1(A) to (D) are cutaway side views of essential parts of a PV type infrared sensing element at key points in the process for explaining the case of manufacturing an embodiment of the present invention, and FIG. x
FIG. 3 is a diagram for explaining the state of the X-value distribution in the Cd x Ta crystal layer, and FIG. 3 is a cross-sectional side view of an essential part of an embodiment of the present invention. Patent Applicant: Fujitsu Ltd. Representative Patent Attorney: Akira Aitani Representative Patent Attorney: Hiroshi Watanabe - (B) Figure 1 (C) (D) Cutaway side view of essential parts for explaining the manufacturing process of one embodiment Figure 1

Claims (1)

【特許請求の範囲】 ＣｄＴｅ結晶基板上にエピタキシャル成長されたＨｇ＿
１＿−＿ｘＣｄ＿ｘＴｅ結晶層の表面から界面近傍のｘ
値が大きい部分に達するまでエッチングして形成された
メサ部分と、 該メサ部分及びその周辺に於いて前記ＣｄＴｅ結晶基板
に到達しない深さに形成されたｐｎ接合と を備えてなることを特徴とするＰＶ型赤外線検知素子。[Claims] Hg grown epitaxially on a CdTe crystal substrate
1_-_xCd_xx near the interface from the surface of the Te crystal layer
A mesa portion formed by etching until reaching a portion with a large value, and a pn junction formed in the mesa portion and its surroundings at a depth that does not reach the CdTe crystal substrate. PV type infrared sensing element.
JP60109429A 1985-05-23 1985-05-23 PV type infrared sensing element Pending JPS61268075A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP60109429A JPS61268075A (en) 1985-05-23 1985-05-23 PV type infrared sensing element

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP60109429A JPS61268075A (en) 1985-05-23 1985-05-23 PV type infrared sensing element

Publications (1)

Publication Number Publication Date
JPS61268075A true JPS61268075A (en) 1986-11-27

Family

ID=14510018

Family Applications (1)

Application Number Title Priority Date Filing Date
JP60109429A Pending JPS61268075A (en) 1985-05-23 1985-05-23 PV type infrared sensing element

Country Status (1)

Country Link
JP (1) JPS61268075A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04318979A (en) * 1991-04-17 1992-11-10 Nec Corp Array type infrared ray sensor and manufacture thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04318979A (en) * 1991-04-17 1992-11-10 Nec Corp Array type infrared ray sensor and manufacture thereof

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