JPS63211686A - Avalanche photodiode - Google Patents
Avalanche photodiodeInfo
- Publication number
- JPS63211686A JPS63211686A JP62046008A JP4600887A JPS63211686A JP S63211686 A JPS63211686 A JP S63211686A JP 62046008 A JP62046008 A JP 62046008A JP 4600887 A JP4600887 A JP 4600887A JP S63211686 A JPS63211686 A JP S63211686A
- Authority
- JP
- Japan
- Prior art keywords
- type
- layer
- light
- electric field
- metal layer
- 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
- 238000009792 diffusion process Methods 0.000 claims abstract description 19
- 230000005684 electric field Effects 0.000 claims abstract description 17
- 239000002184 metal Substances 0.000 claims abstract description 14
- 239000000758 substrate Substances 0.000 claims abstract description 11
- 230000001681 protective effect Effects 0.000 claims abstract description 10
- 230000002093 peripheral effect Effects 0.000 claims 1
- 239000000969 carrier Substances 0.000 abstract description 13
- 238000005530 etching Methods 0.000 abstract description 5
- 230000001747 exhibiting effect Effects 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 36
- 230000000694 effects Effects 0.000 description 7
- 230000015556 catabolic process Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000031700 light absorption Effects 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000011241 protective layer Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 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
- H01L31/08—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
- H01L31/107—Devices sensitive to infrared, visible or ultraviolet radiation characterised by only one potential barrier the potential barrier working in avalanche mode, e.g. avalanche photodiodes
-
- 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
- H01L31/0216—Coatings
- H01L31/02161—Coatings for devices characterised by at least one potential jump barrier or surface barrier
- H01L31/02162—Coatings for devices characterised by at least one potential jump barrier or surface barrier for filtering or shielding light, e.g. multicolour filters for photodetectors
- H01L31/02164—Coatings for devices characterised by at least one potential jump barrier or surface barrier for filtering or shielding light, e.g. multicolour filters for photodetectors for shielding light, e.g. light blocking layers, cold shields for infrared detectors
Landscapes
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Light Receiving Elements (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
この発明は、高速応答を示すアバランシェフォトダイオ
ード(APD)に関するものである。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an avalanche photodiode (APD) that exhibits high-speed response.
従来のシリコンアバランシェフォトダイオード(以下5
i−APDと略す)としては第2図に示すようなp”p
n+形プレーナメサ構造のものがある。Conventional silicon avalanche photodiode (5)
(abbreviated as i-APD) is p''p as shown in Figure 2.
There is one with an n+ type planar mesa structure.
このSi’−APDは、n+形Si基板1上にp形エピ
タキシャル層2を形成した後、メサ溝3を設け、乙のメ
サ溝3の内壁にn+拡散層4を形成し、コンタクト層と
してのp+形拡散層5.保護膜6.アノード電極7.カ
ソード電極82反射防止膜9を形成して得られる。In this Si'-APD, after forming a p-type epitaxial layer 2 on an n+-type Si substrate 1, a mesa groove 3 is provided, and an n+ diffusion layer 4 is formed on the inner wall of the mesa groove 3. p+ type diffusion layer5. Protective film6. Anode electrode7. The cathode electrode 82 is obtained by forming the antireflection film 9.
5i−APDでは一般的にイオン化率の大きいキャリア
(電子)をなだれ領域に注入でき、なだれ領域内での光
キャリアの励起を少なくできれば増倍雑音を小さくでき
る。このためには、第2図に示すように、光吸収層をp
形とし、pn接合10を表面から深い位置に形成すれば
良く、p+pn+形は低雑音特性に有利な構造である。In the 5i-APD, carriers (electrons) with a high ionization rate can generally be injected into the avalanche region, and if the excitation of optical carriers within the avalanche region can be reduced, multiplication noise can be reduced. For this purpose, as shown in FIG.
The pn junction 10 may be formed at a deep position from the surface, and the p+pn+ type is an advantageous structure for low noise characteristics.
また、プレーナメサ構造では、メサ溝3の内壁に沿って
n+形拡散層4が形成され、pn接合10の端部が主表
面で保護膜6で覆われた構造となっており、高い信頼性
が得られるものである。In addition, in the planar mesa structure, an n+ type diffusion layer 4 is formed along the inner wall of the mesa groove 3, and the end of the pn junction 10 is covered with a protective film 6 on the main surface, resulting in high reliability. That's what you get.
このようなp+pn+形プレーナメサ構造の5i−AP
Dに光を入射させ、逆方向電圧を印加していくと、p形
エピクキシャル層2が空乏層化され、入射光により空乏
層内でキャリアが励起され、励起されたキャリアとして
の電子がpn接合1oの近傍のなだれ増倍領域に注入さ
れ、電離衝突が起こり、増倍効果が得られる。印加電圧
を高(していくと、空乏層内の電界強度が高くなり、イ
オン化率が高くなり、キャリアの増倍効果も著しくなる
。5i-AP with such a p+pn+ planar mesa structure
When light is incident on D and a reverse voltage is applied, the p-type epitaxial layer 2 becomes a depletion layer, carriers are excited in the depletion layer by the incident light, and electrons as excited carriers form a p-n junction. It is injected into the avalanche multiplication region near 1o, ionization collision occurs, and a multiplication effect is obtained. As the applied voltage increases, the electric field strength within the depletion layer increases, the ionization rate increases, and the carrier multiplication effect becomes significant.
さらに、印加電圧を高くしていくと、さらに増倍効果が
高まり、急激に逆方向電流が流れる状態となる。この状
態はアバランシェブレークダウンといわれ、この電圧が
降伏電圧となる。Furthermore, as the applied voltage is increased, the multiplication effect further increases, resulting in a state in which a reverse current suddenly flows. This state is called avalanche breakdown, and this voltage is the breakdown voltage.
このようにS i −A P Dでは、キャリアの増倍
効果により素子内部で増倍利得を有することとなり、降
伏電圧近くの電圧を印加して使用すると高い増倍利得が
得られる。In this way, S i -A P D has a multiplication gain inside the element due to the carrier multiplication effect, and a high multiplication gain can be obtained when a voltage close to the breakdown voltage is applied.
また、この場合、光吸収層内には高い電界がかかってお
り、励起キャリアが高速で移動するため高速応答特性を
有する。Further, in this case, a high electric field is applied within the light absorption layer, and the excited carriers move at high speed, so that the light absorption layer has high-speed response characteristics.
上記のような従来のS i −A P Dでは、反射防
止膜9が形成されている受光部以外にも光が入射するこ
とが避けられず、動作時、受光部のp形エピタキシャル
層2では、空乏化されて電界がかかっているため、ここ
で発生した励起キャリアが高速で移動するのに対して、
受光部以外では電界がかかっていないため、励起された
キャリアが拡散によって低速で移動する。このため、応
答速度が低下するという問題点があった。In the conventional Si-APD as described above, it is unavoidable that light enters the light receiving part other than the light receiving part where the antireflection film 9 is formed, and during operation, the p-type epitaxial layer 2 of the light receiving part , the excited carriers generated here move at high speed because they are depleted and an electric field is applied.
Since no electric field is applied to areas other than the light-receiving part, the excited carriers move at low speed due to diffusion. Therefore, there was a problem that the response speed decreased.
この発明は、かかる問題点を解決するなめになされたも
ので、高速応答を示すAPD?!得ることを目的とする
。This invention was made to solve these problems, and is an APD that exhibits high-speed response. ! The purpose is to obtain.
この発明に係るAPDは、電界のかかる受光部を除くp
+形コンタクト層、p形エピタキシャル層、n+形拡散
層およびn+形基板の表面上に形成された保護膜上に遮
光用金属層を設けたものである。The APD according to the present invention has p
A light-shielding metal layer is provided on a protective film formed on the surface of a + type contact layer, a p type epitaxial layer, an n + type diffusion layer, and an n + type substrate.
この発明においては、電界のかかる受光部以外の遮光用
金属層の下の半導体層には光が入射して励起キャリアが
発生せず、電界のかかる受光部で発生する励起キャリア
は電界によって高速で移動する。In this invention, light enters the semiconductor layer under the light-shielding metal layer other than the light-receiving area where the electric field is applied, and no excited carriers are generated, and the excited carriers generated at the light-receiving area where the electric field is applied are accelerated by the electric field. Moving.
第1図はこの発明のAPDの一実施例の構造を示す図で
ある。FIG. 1 is a diagram showing the structure of an embodiment of the APD of the present invention.
この図において、第2図と同一符号は同一部分を示し、
11はメサエッチングにより形成された凹部、12は、
例えばAj等からなる遮光用金属層である。In this figure, the same symbols as in Fig. 2 indicate the same parts,
11 is a recess formed by mesa etching; 12 is a recess formed by mesa etching;
For example, it is a light-shielding metal layer made of Aj or the like.
次にこの発明のAPDの製造工程について説明する。Next, the manufacturing process of the APD of this invention will be explained.
まず、n+形Si基板1上にp形エピタキシャル層2を
形成した後、受光部となる部分を除いてメサエッチング
により凹部11を形成する。次にこの凹部11から拡散
を行ってn+形拡散層4を形成し、次にp+形拡散層5
.保護膜6P反射防止膜9を形成する。この時、保護膜
6は電界のかかる受光部を除くp+形拡散層5p P形
エピタキシャル層2.n+形拡散層4およびn+形Si
基板1上に形成する。そして最後に、写真製版技術を用
いてアノード電極7と遮光用金属層12を同時に形成す
る。ただし、この時、遮光用金属層12は電界のかから
ない領域の保i!膜6上に゛、導電性を有する半導体層
の部分とは接触しないように形成する。First, a p-type epitaxial layer 2 is formed on an n+-type Si substrate 1, and then a recess 11 is formed by mesa etching except for a portion that will become a light receiving section. Next, diffusion is performed from this recess 11 to form an n+ type diffusion layer 4, and then a p+ type diffusion layer 5.
.. A protective film 6P and an antireflection film 9 are formed. At this time, the protective film 6 consists of a p+ type diffusion layer 5p, a p type epitaxial layer 2. n+ type diffusion layer 4 and n+ type Si
Formed on substrate 1. Finally, the anode electrode 7 and the light-shielding metal layer 12 are simultaneously formed using photolithography. However, at this time, the light-shielding metal layer 12 protects the area where no electric field is applied i! It is formed on the film 6 so as not to contact the conductive portion of the semiconductor layer.
すなわち、この発明のAPDは、第1図からも明らかな
ように、遮光用金属層12によって電界のかかる受光部
以外の領域への光の入射が防止されるため、励起キャリ
アはすべて電界のかかる受光部でのみ発生して高速で移
動する。したがって、この発明のAPDは高速応答を示
す。That is, in the APD of the present invention, as is clear from FIG. 1, the light-shielding metal layer 12 prevents light from entering areas other than the light-receiving area where the electric field is applied, so that all of the excited carriers are not exposed to the electric field. It is generated only at the light receiving part and moves at high speed. Therefore, the APD of this invention exhibits fast response.
また、遮光用金属層12は半導体層およびアノード電極
7とは電気的に導通しないように形成されているため、
電極容量を増加させて応答速度を低下させることはない
。Moreover, since the light-shielding metal layer 12 is formed so as not to be electrically conductive with the semiconductor layer and the anode electrode 7,
The response speed is not decreased by increasing the electrode capacitance.
この発明は以上説明したとおり、電界のかかる受光部を
除<p+形コンタクト層、p形エピタキシャル層、n+
形拡散層およびn+形基板の表面上に形成された保護股
上に遮光用金属層を設けたので、電界のかかる受光部以
外への光の入射が防止され、電界のかかっている受光部
のみで励起キャリアが発生し、この励起キャリアが電界
によって高速で移動するため、高速応答を可能にすると
いう効果がある。As explained above, this invention excludes the light-receiving part to which an electric field is applied.
Since a light-shielding metal layer is provided on the protective layer formed on the surface of the type diffusion layer and the n+ type substrate, light is prevented from entering areas other than the light receiving area where the electric field is applied. Excited carriers are generated and these excited carriers move at high speed due to the electric field, which has the effect of enabling high-speed response.
また、遮光用金属層の形成はアノード電極の形成時に同
時に行えるため、APDを高価にする乙となく構成でき
る。Furthermore, since the formation of the light-shielding metal layer can be performed simultaneously with the formation of the anode electrode, it is possible to construct the APD without making it expensive.
第1図はこの発明のAPDの一実施例の構造を示す図、
第2図は従来のS i −A P Dの構造を示す図で
ある。
図において、1はn+形Si基板、2はp形エピタキシ
ャル層、4はn+形拡散層、5はp+形拡散層、6は保
護膜、7はアノード電極、8はカソードTi極、9は反
射防止膜、1oはpn接合、11はメサエッチングによ
り形成された凹部、12は遮光用金属層である。
なお、各図中の同一符号は同一または相当部分を示す。FIG. 1 is a diagram showing the structure of an embodiment of the APD of the present invention,
FIG. 2 is a diagram showing the structure of a conventional S i -APD. In the figure, 1 is an n + type Si substrate, 2 is a p type epitaxial layer, 4 is an n + type diffusion layer, 5 is a p + type diffusion layer, 6 is a protective film, 7 is an anode electrode, 8 is a cathode Ti pole, 9 is a reflection In the prevention film, 1o is a pn junction, 11 is a recess formed by mesa etching, and 12 is a light-shielding metal layer. Note that the same reference numerals in each figure indicate the same or corresponding parts.
Claims (1)
このp形エピタキシャル層の表面の一部領域に形成され
たp^+形コンタクト層と、前記p形エピタキシャル層
の外周部の表面から前記n^+形基板まで形成されたn
^+形拡散層と、電界のかかる受光部を除く前記p^+
形コンタクト層、前記p形エピタキシャル層、前記n^
+形拡散層および前記n^+形基板の表面上に形成され
た保護膜とから構成されるプレーナメサ構造のアバラン
シエフオトダイオードにおいて、前記保護膜上に遮光用
金属層を設けたことを特徴とするアバランシエフオトダ
イオード。a p-type epitaxial layer formed on an n^+-type substrate;
A p^+ type contact layer formed on a partial region of the surface of the p type epitaxial layer, and an n^+ type contact layer formed from the outer peripheral surface of the p type epitaxial layer to the n^+ type substrate.
The above p^+ excluding the ^+ type diffusion layer and the light receiving part where the electric field is applied
type contact layer, said p type epitaxial layer, said n^
An avalanche photodiode having a planar mesa structure comprising a + type diffusion layer and a protective film formed on the surface of the n^+ type substrate, characterized in that a light shielding metal layer is provided on the protective film. Avalanche photodiode.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP62046008A JPS63211686A (en) | 1987-02-26 | 1987-02-26 | Avalanche photodiode |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP62046008A JPS63211686A (en) | 1987-02-26 | 1987-02-26 | Avalanche photodiode |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS63211686A true JPS63211686A (en) | 1988-09-02 |
Family
ID=12735037
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP62046008A Pending JPS63211686A (en) | 1987-02-26 | 1987-02-26 | Avalanche photodiode |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS63211686A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0444963A2 (en) * | 1990-03-02 | 1991-09-04 | Canon Kabushiki Kaisha | Photoelectric transfer device |
JPH04369273A (en) * | 1991-06-18 | 1992-12-22 | Fujitsu Ltd | Infrared ray sensor |
JPH05175539A (en) * | 1991-12-25 | 1993-07-13 | Mitsubishi Electric Corp | Semiconductor light receiver and manufacture thereof |
US8558339B1 (en) | 2013-03-01 | 2013-10-15 | Mitsubishi Electric Corporation | Photo diode array |
-
1987
- 1987-02-26 JP JP62046008A patent/JPS63211686A/en active Pending
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0444963A2 (en) * | 1990-03-02 | 1991-09-04 | Canon Kabushiki Kaisha | Photoelectric transfer device |
JPH04369273A (en) * | 1991-06-18 | 1992-12-22 | Fujitsu Ltd | Infrared ray sensor |
JPH05175539A (en) * | 1991-12-25 | 1993-07-13 | Mitsubishi Electric Corp | Semiconductor light receiver and manufacture thereof |
US8558339B1 (en) | 2013-03-01 | 2013-10-15 | Mitsubishi Electric Corporation | Photo diode array |
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