JPH0562472B2 - - Google Patents
Info
- Publication number
- JPH0562472B2 JPH0562472B2 JP57200570A JP20057082A JPH0562472B2 JP H0562472 B2 JPH0562472 B2 JP H0562472B2 JP 57200570 A JP57200570 A JP 57200570A JP 20057082 A JP20057082 A JP 20057082A JP H0562472 B2 JPH0562472 B2 JP H0562472B2
- Authority
- JP
- Japan
- Prior art keywords
- inp
- layer
- diameter
- photodetection layer
- photodetection
- 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.)
- Expired - Lifetime
Links
- 239000000758 substrate Substances 0.000 claims description 11
- 239000004065 semiconductor Substances 0.000 claims description 9
- 238000000034 method Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000013307 optical fiber Substances 0.000 description 3
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 239000013078 crystal Substances 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000001451 molecular beam epitaxy Methods 0.000 description 1
- 229920002120 photoresistant polymer Polymers 0.000 description 1
- 238000001947 vapour-phase growth 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
- H01L31/02—Details
- H01L31/0232—Optical elements or arrangements associated with the device
- H01L31/02325—Optical elements or arrangements associated with the device the optical elements not being integrated nor being directly associated with the device
Description
【発明の詳細な説明】
本発明は、光通信用の光検出器、特に波長1.0
〜1.6μｍ帯の長波長帯の光通信に用いるIn1-xGax
AsyP1-y／InP系（Ｘ、Ｙ≠０）フオトダイオー
ド（PINダイオードあるいはアバランシエフオト
ダイオードを含む）に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photodetector for optical communication, particularly a photodetector with a wavelength of 1.0.
In 1-x Ga x used for optical communication in the long wavelength band ~1.6μm band
As y P 1-y /InP-based (X, Y≠0) photodiode (including PIN diode or avalanche photodiode).
最近、In1-xGaxAsyP1-y／InP系（Ｘ、Ｙ≠０）
フオトダイオードは盛んに開発が進められてい
る。 Recently, In 1-x Ga x As y P 1-y /InP system (X, Y≠0)
Photodiodes are being actively developed.
一般にフオトダイオードにおいては、暗電流及
び静電容量も小さい程、高性能になることは良く
知られている。暗電流及び静電容量を小さくする
には、受光部のPN接合の面積を小さくすれば良
いことは明らかである。しかしながらPN接合の
面積をあまり、小さくすると、光フアイバとフオ
トダイオードの結合効率が劣化するため、PN接
合の面積をむやみに小さくすることは出来ない。
したがつて、従来のフオトダイオードではPN接
合の面積をあまり小さくすることが出来ないた
め、暗電流及び静電容量を小さくすることが出来
ないという欠点があつた。 In general, it is well known that the smaller the dark current and capacitance of a photodiode, the higher the performance. It is clear that in order to reduce dark current and capacitance, it is sufficient to reduce the area of the PN junction in the light receiving section. However, if the area of the PN junction is made too small, the coupling efficiency between the optical fiber and the photodiode will deteriorate, so the area of the PN junction cannot be reduced unnecessarily.
Therefore, in conventional photodiodes, the area of the PN junction cannot be made very small, so the dark current and capacitance cannot be made small.
本発明の目的は、光フアイバと結合効率を劣化
させることなく、暗電流及び静電容量の小さなフ
オトダイオードを提供することにある。 An object of the present invention is to provide a photodiode with low dark current and low capacitance without deteriorating coupling efficiency with an optical fiber.
本発明の光検出器は、半導体基板の主両側に形
成され、前記半導体基板に比し小さな禁制帯幅を
有し、直径D1のほぼ円形の受光部を有する光検
出層と該光検出層に対して凹面鏡となるように、
前記主面に対向する半導体基板面の前記光検出層
の下に位置する部分を半導体外部に向かつて凸状
とした直径D2（D2＞D1）および焦点距離ｆの反射
鏡を具備し、前記光検出層から前記反射鏡までの
距離をＬとしたときＬ≦ｆであることを特徴とす
る。 The photodetector of the present invention includes a photodetection layer formed on both main sides of a semiconductor substrate, which has a smaller forbidden band width than the semiconductor substrate and has a substantially circular light receiving portion with a diameter D1 ; As if it were a concave mirror,
A reflecting mirror having a diameter D 2 (D 2 >D 1 ) and a focal length f is provided, with a portion of the semiconductor substrate surface facing the principal surface located below the photodetection layer being convex toward the outside of the semiconductor. , L≦f, where L is a distance from the photodetection layer to the reflecting mirror.
以下図面を参照して本発明を詳しく説明する。 The present invention will be described in detail below with reference to the drawings.
図は、本発明の一実施例のフオトダイオードの
断面図である。 The figure is a sectional view of a photodiode according to an embodiment of the present invention.
図中、１はｎ・InP基板、２はｎ・InPバツフ
アー層、３はIn1-xGaxAsyP1-y（Ｘ、Ｙ≠０）から
なる光検出層、４はβ・InPウインドウ層、５は
ｐ電極、６はｎ電極、７は反射鏡、８はAu等の
反射金属、９は入射光、１０は無反射コーテイン
グである。光検出層３の位置は反射鏡７の焦点も
しくは焦点よりも反射鏡に近いところにある。こ
のときは、光検出層３の虚像が反射鏡７によつて
でき、その直径D2は、実際の光検出層３の直径
D1よりも大きくなる。従がつて入射光９に対す
る受光径はD2であるので、D2を光フアイバの入
射光を受けるだけの大きさに保つたまま、光検出
層３の直径D1を小さくすることが出来る。例え
ば、反射鏡７の焦点距離が125μｍ（曲率半径
250μｍ）で、反射鏡７と光検出層３の距離が
105μｍの場合には、光検出層３（直径D1）のほ
ぼ６倍の大きさの虚像が形成される。したがつ
て、反射鏡７の直径D2を180μｍとすると、光検
出層は直径（＝D1）30μｍの小さな受光部とする
事が出来る。光検出層の直径D1を小さくするこ
とにより、暗電流及び静電容量が小さなフオトダ
イオードが実現出来た。又、この様な構造では、
ｐ電極５の下の光検出層３も光検出に有効な効果
を持つため受光面積は上から入射するだけの場合
に比べて大きくなる利点を有する。さらに光検出
層３が2μｍ以下の比較的薄い場合には上から入
射して来る光を100％吸収出来ないが反射鏡７で
反射した光をもう一度吸収出来るので見かけ上光
検出層３の厚さが２倍になつたと同じ効果を有す
る。 In the figure, 1 is an n-InP substrate, 2 is an n-InP buffer layer, 3 is a photodetection layer consisting of In 1-x Ga x As y P 1-y (X, Y≠0), and 4 is β-InP In the window layer, 5 is a p-electrode, 6 is an n-electrode, 7 is a reflective mirror, 8 is a reflective metal such as Au, 9 is incident light, and 10 is a non-reflective coating. The position of the photodetection layer 3 is at the focal point of the reflecting mirror 7 or closer to the reflecting mirror than the focal point. At this time, a virtual image of the photodetection layer 3 is created by the reflecting mirror 7, and its diameter D 2 is the actual diameter of the photodetection layer 3.
D will be greater than 1 . Therefore, since the receiving diameter for the incident light 9 is D 2 , the diameter D 1 of the photodetecting layer 3 can be reduced while keeping D 2 large enough to receive the incident light of the optical fiber. For example, the focal length of the reflector 7 is 125 μm (curvature radius
250 μm), and the distance between the reflecting mirror 7 and the photodetection layer 3 is
In the case of 105 μm, a virtual image approximately six times the size of the photodetection layer 3 (diameter D 1 ) is formed. Therefore, if the diameter D 2 of the reflecting mirror 7 is 180 μm, the photodetection layer can be made into a small light-receiving portion with a diameter (=D 1 ) of 30 μm. By reducing the diameter D 1 of the photodetection layer, a photodiode with low dark current and low capacitance was realized. Also, in such a structure,
Since the photodetection layer 3 under the p-electrode 5 also has an effective effect on photodetection, the light-receiving area has the advantage of being larger than when light is only incident from above. Furthermore, if the photodetection layer 3 is relatively thin (2 μm or less), it cannot absorb 100% of the light incident from above, but it can absorb the light reflected by the reflector 7 again, so the apparent thickness of the photodetection layer 3 has the same effect as doubling.
さて次に、製作方法の一例について簡単に説明
する。 Next, an example of the manufacturing method will be briefly explained.
まず、ｎ・InP基板１上にｎ・InPバツフアー
層２を３〜10μｍ成長し、次に光検出層３（In1-x
GaxAsyP1-yＸ、Ｙ≠０）を１〜5μｍ成長し、次
にｐ・InP層を１〜3μｍ成長する。成長方法は、
液相成長法気相成長法、分子線エピタクシー法等
の成長方法によつても良い。 First, an n-InP buffer layer 2 with a thickness of 3 to 10 μm is grown on an n-InP substrate 1, and then a photodetection layer 3 (In 1-x
Ga x As y P 1- y The growth method is
Growth methods such as liquid phase growth, vapor phase growth, and molecular beam epitaxy may also be used.
次に、良好なオーミツク接触を得るためにZn
拡散を行なつた後ｐ電極５を形成する。次にｐ電
極５の真下に合わせて反射鏡７を形成する。これ
は円形にパターン化したフオトレジストを熱処理
して球面にしたものをマスクとしてイオンビーム
エツチングをすることにより、裏面に凸状の球面
を形成する。 Next, in order to obtain good ohmic contact, Zn
After the diffusion, a p-electrode 5 is formed. Next, a reflecting mirror 7 is formed directly below the p-electrode 5. In this method, a convex spherical surface is formed on the back surface by performing ion beam etching using a circularly patterned photoresist that has been heat-treated to form a spherical surface as a mask.
次に反射金属８及びｎ電極６を同じ電極材を用
いて形成する。次に光検出層３の深さまでメサエ
ツチングをして、最後に無反射コーテイング１０
を形成する。 Next, the reflective metal 8 and the n-electrode 6 are formed using the same electrode material. Next, mesa etching is performed to the depth of the photodetection layer 3, and finally a non-reflective coating 10 is applied.
form.
本実施例においては、光検出層３の上にｐ・
InPウインドウ層４が形成されているが、これに
限らず、光検出層と同一組成のｐ型半導体でも良
い。あるいは、ｎ−InP／ｐ・InPやｎ−
InGaAsP／ｎ−InP／Ｐ・InP等の多層構造とな
つていても良い。又、本実施例は、フオトダイオ
ードとしているが、これは、同構造のPINダイオ
ードあるいはアバランシエフオトダイオードを含
んでおり、本実施例と同様な効果があることは明
らかである。又、本実施例ではｐ・InPに直接ｐ
電極を形成していたが、ｐ・InPとｐ電極の間に
ｐ・InGaAsP等からなる電極層を形成しても良
い。又本実施例ではｎ電極６は裏面に形成した
が、上面に形成しても良い。この場合はｎ・InP
基板１のかわりに反絶縁性InP基板を用いても良
い。又、本実施例では、結晶成長によつてｐ・
InPウインドウ層４を形成したが、結晶成長にお
いてはｎ−InPを形成し、後にｐ型不純物を拡散
等の技術を用いて導入することによりｎ・InPを
ｐ・InPに変えても良い。 In this example, p.
Although the InP window layer 4 is formed, it is not limited to this, and may be a p-type semiconductor having the same composition as the photodetection layer. Alternatively, n-InP/p・InP or n-InP
It may have a multilayer structure such as InGaAsP/n-InP/P.InP. Further, although this embodiment uses a photodiode, it includes a PIN diode or an avalanche photodiode having the same structure, and it is clear that it has the same effect as this embodiment. In addition, in this example, p is directly connected to p InP.
Although an electrode is formed in the above example, an electrode layer made of p.InGaAsP or the like may be formed between the p.InP and the p electrode. Further, in this embodiment, the n-electrode 6 is formed on the back surface, but it may be formed on the top surface. In this case, n・InP
An anti-insulating InP substrate may be used instead of the substrate 1. In addition, in this example, p.
Although the InP window layer 4 is formed, n-InP may be formed during crystal growth, and then n-InP may be changed to p-InP by introducing p-type impurities using a technique such as diffusion.
図は本発明の一実施例の光検出器の断面図であ
る。
図中、１はｎ・InP基板、２はｎ・InPバツフ
アー層、３は光検出層、４はｐ・InPウインドウ
層、５はｐ電極、６はｎ電極、７は反射鏡、８は
反射金属、９は入射光、１０は無反射コーテイン
グである。
The figure is a sectional view of a photodetector according to an embodiment of the present invention. In the figure, 1 is an n-InP substrate, 2 is an n-InP buffer layer, 3 is a photodetection layer, 4 is a p-InP window layer, 5 is a p-electrode, 6 is an n-electrode, 7 is a reflective mirror, and 8 is a reflective 9 is a metal, 9 is an incident light, and 10 is a non-reflection coating.
Claims (1)
基板に比し小さな禁制帯幅を有し、直径D1のほ
ぼ円形の受光部を有する光検出層と該光検出層に
対して凹面鏡となるように、前記主面に対向する
半導体基板面の前記光検出層の下に位置する部分
を半導体外部に向かつて凸状とした直径D2（D2＞
D1）および焦点距離ｆの反射鏡を具備し、前記
光検出層から前記反射鏡までの距離をＬとしたと
きＬ≦ｆであることを特徴とする光検出器。1. A photodetection layer formed on both main sides of the semiconductor substrate, having a smaller forbidden band width than the semiconductor substrate, and having a substantially circular light-receiving portion with a diameter D 1 ; A portion of the semiconductor substrate surface facing the main surface, located below the photodetection layer, is made convex toward the outside of the semiconductor with a diameter D 2 (D 2 >
D 1 ) and a reflecting mirror having a focal length f, and where L is a distance from the photodetecting layer to the reflecting mirror, L≦f.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57200570A JPS5990964A (en) | 1982-11-16 | 1982-11-16 | Photodetector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57200570A JPS5990964A (en) | 1982-11-16 | 1982-11-16 | Photodetector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5990964A JPS5990964A (en) | 1984-05-25 |
| JPH0562472B2 true JPH0562472B2 (en) | 1993-09-08 |
Family
ID=16426520
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57200570A Granted JPS5990964A (en) | 1982-11-16 | 1982-11-16 | Photodetector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5990964A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62281374A (en) * | 1986-05-29 | 1987-12-07 | Omron Tateisi Electronics Co | Semiconductor device |
| DE19518303C2 (en) * | 1995-05-18 | 1997-04-10 | Forschungszentrum Juelich Gmbh | Optical lens / detector arrangement |
| JP6035770B2 (en) * | 2012-02-20 | 2016-11-30 | 日本電気株式会社 | Semiconductor photo detector |
| US11145770B2 (en) | 2018-02-01 | 2021-10-12 | Kyoto Semiconductor Co., Ltd. | Semiconductor light receiving element |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55162284A (en) * | 1979-06-01 | 1980-12-17 | Mitsubishi Electric Corp | Light emitting diode and its manufacturing method |
-
1982
- 1982-11-16 JP JP57200570A patent/JPS5990964A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55162284A (en) * | 1979-06-01 | 1980-12-17 | Mitsubishi Electric Corp | Light emitting diode and its manufacturing method |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5990964A (en) | 1984-05-25 |
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