JPH07120815B2 - Phototransistor - Google Patents
PhototransistorInfo
- Publication number
- JPH07120815B2 JPH07120815B2 JP61217460A JP21746086A JPH07120815B2 JP H07120815 B2 JPH07120815 B2 JP H07120815B2 JP 61217460 A JP61217460 A JP 61217460A JP 21746086 A JP21746086 A JP 21746086A JP H07120815 B2 JPH07120815 B2 JP H07120815B2
- Authority
- JP
- Japan
- Prior art keywords
- region
- phototransistor
- base
- collector
- type
- 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
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
- H10F30/24—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 two potential barriers, e.g. bipolar phototransistors
- H10F30/245—Bipolar phototransistors
Landscapes
- Light Receiving Elements (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 本発明は光電変換素子として用いられているフォトトラ
ンジスタに関する。TECHNICAL FIELD The present invention relates to a phototransistor used as a photoelectric conversion element.
従来の技術 従来から用いられているフォトトランジスタの断面構造
を、第２図に示す。図中２はN+型基板１上にエピタキシ
ャル成長で形成されたＮ型のエピタキシャル層で、フォ
トトランジスタのコレクタとなる領域、３はエピタキシ
ャル層２の中に形成されたＰ型領域で、フォトトランジ
スタのベース領域、４はベース領域中に形成されたN+型
領域で、フォトトランジスタのエミッタ領域、５及び６
はそれぞれコレクタ及びエミッタ電極、７は不透明膜で
ある。2. Description of the Related Art FIG. 2 shows a cross-sectional structure of a phototransistor which has been conventionally used. In the figure, 2 is an N-type epitaxial layer formed by epitaxial growth on the N + -type substrate 1, a region serving as a collector of the phototransistor, and 3 is a P-type region formed in the epitaxial layer 2, The base region 4 is an N + type region formed in the base region, and is the emitter region of the phototransistor 5 and 6.
Are collector and emitter electrodes, and 7 is an opaque film.
通常のトランジスタでは、ベース領域にベース電極が設
けられており、ここを通してキャリアーを注入すること
により、トランジスタを動作させるのであるが、フォト
トランジスタに於ては、光に対して露出されたベース領
域に光９を当てることにより、ベース領域にキャリアー
を発生させトランジスタ動作を行なわせ、ベースに与え
た光の信号を、フォトトランジスタのエミッタ又はコレ
クタから電気信号として取り出している。In a normal transistor, a base electrode is provided in the base region, and a transistor is operated by injecting carriers through the base electrode.However, in a phototransistor, the base electrode is exposed to light. When light 9 is applied, carriers are generated in the base region to perform transistor operation, and the light signal given to the base is taken out as an electric signal from the emitter or collector of the phototransistor.
発明が解決しようとする問題点 フォトトランジスタにより、光信号を電気信号に変換す
る場合、光信号があるか、ないかを明確に判別するため
に、フォトトランジスタの動作状態を飽和状態に設定し
て使用する場合が多い。第３図はこのような使用例を示
すもので、光信号９を電気信号に変換し、コレクタ電極
５から負荷抵抗11の端部の電圧変化としてとり出すので
あるが、光信号のある場合の電極５の出力レベルを明確
にするために、フォトトランジスタ10の動作状態を飽和
状態に設定して使用するべく、抵抗11の値と光信号９の
強度が設定される。Problems to be Solved by the Invention When a phototransistor converts an optical signal into an electric signal, the operating state of the phototransistor is set to a saturated state in order to clearly determine whether or not there is an optical signal. Often used. FIG. 3 shows an example of such a use, in which the optical signal 9 is converted into an electric signal and is taken out from the collector electrode 5 as a voltage change at the end of the load resistor 11. In order to clarify the output level of the electrode 5, the value of the resistor 11 and the intensity of the optical signal 9 are set so that the operation state of the phototransistor 10 is set to the saturated state and used.
ところで、フォトトランジスタのばらつき、例えば光入
力に対するコレクタ電流のばらつきは数倍にもなること
があり、使用温度範囲も考慮に入れると、設定条件に対
し光信号の強度が十分に大であることが安定な動作には
必須の要件となる。しかしながら、このように設計する
と、フォトトランジスタ10は過飽和の状態で動作するこ
ととなり、入力信号である光信号９をしゃ断しても、ベ
ース領域に過剰に蓄積されたキャリアーにより、しばら
くの間は導通状態を保つ。このことは、フォトトランジ
スタの応答速度が低いことを意味し、高速動作が要求さ
れる応用には不適当といわねばならない。By the way, the variation of the phototransistor, for example, the variation of the collector current with respect to the light input may become several times, and when the operating temperature range is taken into consideration, the intensity of the optical signal may be sufficiently large with respect to the set condition. It is an essential requirement for stable operation. However, if designed in this way, the phototransistor 10 will operate in a supersaturated state, and even if the optical signal 9 that is the input signal is cut off, the phototransistor 10 will remain conductive for a while due to excessive carriers accumulated in the base region. Keep the state. This means that the response speed of the phototransistor is low, and it must be said that it is unsuitable for applications requiring high-speed operation.
問題点を解決するための手段 この問題点を解決するために、本発明ではフォトトラン
ジスタのコレクタ領域となる第１の領域、第１の領域の
中に形成されたこれとは反対導電型の第２の領域、第２
の領域の中に形成された第１の領域と同導電型の第３の
領域、第２の領域に隣接し、かつ、これと同導電型の第
４の領域を有し、第１の領域がコレクタ、第２の領域が
ベース、第３の領域がエミッタとなる第１のトランジス
タと、第２の領域がエミッタ、第１の領域がベース、第
４の領域がコレクタとなる第２のトランジスタとを備
え、第１と第２のトランジスタは互いに逆導電型の関係
を有し、かつ、第３の領域と第４の領域は電気的に接続
した構造としている。Means for Solving the Problems In order to solve this problem, in the present invention, a first region serving as a collector region of a phototransistor and a first region of the opposite conductivity type formed in the first region are formed. 2nd area, 2nd
A third region having the same conductivity type as the first region and a fourth region adjacent to the second region and having the same conductivity type as the first region formed in the first region; Is the collector, the second region is the base, and the third region is the emitter, and the second transistor is the second region, which is the emitter, the first region is the base, and the fourth region is the collector. And the first and second transistors have a relationship of opposite conductivity type to each other, and the third region and the fourth region are electrically connected.
作用 ベースに光信号が入ると、フォトトランジスタは導通す
る。フォトトランジスタを含む回路は、安定な動作を保
証するため、フォトトランジスタの飽和状態が深くなる
ように設計されているが、一度フォトトランジスタが軽
い飽和状態に入ると、ベースとコレクタ間のPN接合が順
方向にバイアスされ、ベース領域をエミッタとし、コレ
クタ領域をベースとし、さらにベース領域をとり囲む関
係で形成されたＰ型領域をコレクタとするPNPトランジ
スタが動作し、必要以上に強い光信号が入力されること
によりベース領域で過剰なキャリアーが発生しても、こ
の過剰なキャリアーはPNPトランジスタによりとり除か
れる。したがって、光信号がなくなった場合に、フォト
トランジスタが速やかにしゃ断状態に入り高速動作が実
現できる。When an optical signal enters the base, the phototransistor becomes conductive. The circuit including the phototransistor is designed so that the saturation state of the phototransistor is deep in order to guarantee stable operation, but once the phototransistor enters a light saturation state, the PN junction between the base and the collector is formed. A PNP transistor that is biased in the forward direction and uses the base region as the emitter, the collector region as the base, and the P-type region formed by the relationship surrounding the base region as the collector operates to input an unnecessarily strong optical signal. Even if excess carriers are generated in the base region due to this, the excess carriers are removed by the PNP transistor. Therefore, when the optical signal disappears, the phototransistor enters the cutoff state promptly and high speed operation can be realized.
実 施 例 第１図ａ及びｂを用いて本発明を説明する。第１図ａは
本発明のフォトトランジスタの断面図、ｂは本発明のフ
ォトトランジスタの動作を理解するための等価回路図で
ある。図中１〜７は第２図で同一番号を付して示した部
分と同一の部分である。本発明のフォトトランジスタ
は、Ｎ型エピタキシャル層（第１の領域）２の中にＰ型
領域（第２の領域）３が形成されている。Ｐ型領域の中
にはＮ型エピタキシャル層２と同じ導電型のＮ型領域
（第３の領域）４が形成されている。こうした構成下に
おいては、エピタキシャル層２がコレクタ、Ｐ型領域３
がベース、Ｎ型領域４がエミッタとなる第１のトランジ
スタが形成される。ベースであるＰ型領域３は光信号９
を受け入れる。Ｎ型領域４にはエミッタ電極６が接続さ
れている。また、Ｐ型領域３に隣接させてこれと同じ導
電型のＰ型領域（第４の領域）８が形成されている。こ
うした構成によって、Ｐ型領域３がエミッタ、Ｎ型エピ
タキシャル層２がベース、Ｐ型領域８がコレクタとなる
第２のトランジスタが形成されるものとなる。しかも、
このＰ型領域８をエミッタ電極６と電気的に接続した構
造とされている。このような構造とするならば、光信号
の入力によりフォトトランジスタ10（NPNトランジス
タ）が飽和状態に入ると、ベース３とコレクタ２の間が
順方向になり、光信号９により過剰に生成されたキャリ
アーは、ベース領域３をエミッタとし、コレクタ領域２
をベースとし、Ｐ型領域８をコレクタとするPNPトラン
ジスタを通り、エミッタ電極６へと流れる。したがっ
て、過剰なキャリアーがベース領域３に蓄積されること
はなく、光信号９がなくなった場合には、フォトトラン
ジスタ10は速やかにしゃ断し、高速動作が実現されると
ころとなる。Example The present invention will be described with reference to FIGS. 1A and 1B. FIG. 1a is a sectional view of a phototransistor of the present invention, and b is an equivalent circuit diagram for understanding the operation of the phototransistor of the present invention. In the figure, 1 to 7 are the same parts as those shown by attaching the same numbers in FIG. In the phototransistor of the present invention, a P-type region (second region) 3 is formed in an N-type epitaxial layer (first region) 2. An N-type region (third region) 4 having the same conductivity type as the N-type epitaxial layer 2 is formed in the P-type region. Under this structure, the epitaxial layer 2 is the collector and the P-type region 3 is
Forming a first transistor having a base and an N-type region 4 as an emitter. The P-type region 3 which is the base is an optical signal 9
Accept. An emitter electrode 6 is connected to the N-type region 4. Further, a P-type region (fourth region) 8 having the same conductivity type as that of the P-type region 3 is formed adjacent to the P-type region 3. With this structure, a second transistor having the P-type region 3 as an emitter, the N-type epitaxial layer 2 as a base, and the P-type region 8 as a collector is formed. Moreover,
This P-type region 8 is electrically connected to the emitter electrode 6. With such a structure, when the phototransistor 10 (NPN transistor) enters a saturation state due to the input of the optical signal, the base 3 and the collector 2 are in the forward direction, and the optical signal 9 excessively generates them. The carrier uses the base region 3 as an emitter and the collector region 2 as a carrier.
Through the PNP transistor having the P-type region 8 as the collector and flowing to the emitter electrode 6. Therefore, excessive carriers are not accumulated in the base region 3, and when the optical signal 9 disappears, the phototransistor 10 is immediately shut off, and high-speed operation is realized.
発明の効果 本発明によれば、簡単な構成でフォトトランジスタの動
作速度を飛躍的に向上させる効果が奏される。ちなみに
第１図中のＰ型領域８は、ベース領域３の形成工程で同
時に作ることが可能であり、フォトトランジスタの製作
にあたり何ら不利益をもたらす要因はなく、高速で安価
なフォトトランジスタを提供することが出来る。EFFECTS OF THE INVENTION According to the present invention, it is possible to dramatically improve the operation speed of the phototransistor with a simple configuration. By the way, the P-type region 8 in FIG. 1 can be formed at the same time in the process of forming the base region 3, and there is no factor causing any disadvantage in manufacturing the phototransistor, and a high-speed and inexpensive phototransistor is provided. You can
第１図ａ及びｂは、本発明にかかるフォトトランジスタ
の断面構造と等価回路を示す図、第２図は従来例のフォ
トトランジスタの断面図、第３図は従来例の問題点を説
明するための回路図である。 １……N+型基板、２……Ｎ型エピタキシャル層（コレク
タ）、３……Ｐ型領域（ベース）、４……Ｎ型領域（エ
ミッタ）、５……コレクタ電極、６……エミッタ電極、
７……不透明膜、８……Ｐ型領域、９……光信号（入力
信号）、10……フォトトランジスタ、11……負荷抵抗。1A and 1B are views showing a cross-sectional structure and an equivalent circuit of a phototransistor according to the present invention, FIG. 2 is a cross-sectional view of a conventional phototransistor, and FIG. 3 is a view for explaining problems of the conventional example. It is a circuit diagram of. 1 ... N + type substrate, 2 ... N type epitaxial layer (collector), 3 ... P type region (base), 4 ... N type region (emitter), 5 ... collector electrode, 6 ... emitter electrode ,
7 ... Opaque film, 8 ... P-type region, 9 ... Optical signal (input signal), 10 ... Phototransistor, 11 ... Load resistance.
Claims (1)
第１の領域、第１の領域の中に形成されたこれとは反対
導電型の第２の領域、第２の領域の中に形成された第１
の領域と同導電型の第３の領域、第２の領域に隣接し、
かつ、これと同導電型の第４の領域を有し、第１の領域
がコレクタ、第２の領域がベース、第３の領域がエミッ
タとなる第１のトランジスタと、第２の領域がエミッ
タ、第１の領域がベース、第４の領域がコレクタとなる
第２のトランジスタとを備え、第１と第２のトランジス
タは互いに逆導電型の関係を有し、かつ、第３の領域と
第４の領域は電気的に接続されていることを特徴とする
フォトトランジスタ。1. A first region serving as a collector region of a phototransistor, a second region formed in the first region and having a conductivity type opposite to that of the first region, and a second region formed in the second region. 1
Adjacent to the third and second regions of the same conductivity type as the region
And a first transistor having a fourth region of the same conductivity type as the first region, the first region being a collector, the second region being a base, and the third region being an emitter; and the second region being an emitter. A second transistor having the first region as a base and the fourth region as a collector, wherein the first and second transistors have an opposite conductivity type relationship to each other, and the third region and the third region. A region 4 is a phototransistor, which is electrically connected.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61217460A JPH07120815B2 (en) | 1986-09-16 | 1986-09-16 | Phototransistor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61217460A JPH07120815B2 (en) | 1986-09-16 | 1986-09-16 | Phototransistor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6373568A JPS6373568A (en) | 1988-04-04 |
| JPH07120815B2 true JPH07120815B2 (en) | 1995-12-20 |
Family
ID=16704575
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61217460A Expired - Lifetime JPH07120815B2 (en) | 1986-09-16 | 1986-09-16 | Phototransistor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07120815B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI222219B (en) * | 2003-09-10 | 2004-10-11 | Ind Tech Res Inst | Semiconductor optical transistor |
| TR201612947A2 (en) * | 2016-09-09 | 2018-03-21 | Utku Bueyueksahin | Biomechanical data transmission systems. |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58193B2 (en) * | 1978-08-08 | 1983-01-05 | 日本電信電話株式会社 | Semiconductor optical detection device |
-
1986
- 1986-09-16 JP JP61217460A patent/JPH07120815B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6373568A (en) | 1988-04-04 |
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