JPH09293856A

JPH09293856A - Insulation gate bipolar transistor provided with built-in current detecting part

Info

Publication number: JPH09293856A
Application number: JP10489996A
Authority: JP
Inventors: Yasuyuki Hoshi; 保幸星; Tatsuhiko Fujihira; 龍彦藤平; Seiji Momota; 聖自百田; Motoi Kudo; 基工藤
Original assignee: Fuji Electric Co Ltd
Current assignee: Fuji Electric Co Ltd
Priority date: 1996-04-25
Filing date: 1996-04-25
Publication date: 1997-11-11
Anticipated expiration: 2016-04-25
Also published as: JP3911719B2

Abstract

PROBLEM TO BE SOLVED: To improve the current detection precision of an insulation gate bipolar transistor(IGBT) provided with built-in current detecting part, which detects a current based on voltage drop, by commonly providing a main IGBT part and a sense IGBT part formed with a part of it, and making the current diverted with the sense IGBT part to flow to a sense resistor. SOLUTION: A current-voltage characteristics of a sense IGBT part 14 at gate-on is made approximately linear within the range below the on voltage of a detected current of a main IGBT part 13. Specifically, a P sense base area may be a single stripe, the width of a sense gate electrode 27 between sense emitter electrodes 28 may be narrower than a gate electrode 7 between emitter electrodes 8 of the main IGBT part 14, a gate threshold value of the sense IGBT part 14 may be higher than that of the main IGBT part 13, so that conductivity modulation of the sense IGBT part 14 is hard to occur. A discontinuous point becomes hard to occur with a sense voltage, and the temperature dependency is improved.

Description

Detailed Description of the Invention

【０００１】[0001]

【発明の属する技術分野】本発明は、インバータ装置等
に使用する温度検知部を備えた少数キャリア注入型半導
体素子に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a minority carrier injection type semiconductor device equipped with a temperature detector used in an inverter device or the like.

【０００２】[0002]

【従来の技術】少数キャリア注入型のいわゆるバイポー
ラ半導体素子（ＩＧＢＴ、バイポーラトランジスタ等）
はインバータ等に使用され、最近では、ＩＧＢＴがバイ
ポーラトランジスタに置き変わって市場を拡大してきて
いる。ＩＧＢＴは主に総合損失と安全動作領域の特性向
上を重点に開発されてきたが、近年は高機能化および取
扱の容易さに関しての要求が強まってきている。これら
の多彩な要求に応えるにはＩＧＢＴ単体では限界が出て
きており、ＩＧＢＴ等のパワーデバイスのインテリジェ
ント化によって対応しようとしている。インテリジェン
ト化とは、パワーデバイスとそれらの周辺回路を一体化
することによってそれぞれの弱点を補いつつ高機能化を
図るものであり、例えば、ＩＰＭ（インテリジェントパ
ワーモジュール）はその初めの一つとして登場したデバ
イスである。2. Description of the Related Art Minority carrier injection type so-called bipolar semiconductor devices (IGBTs, bipolar transistors, etc.)
Are used for inverters and the like, and recently, IGBTs have been replaced by bipolar transistors and the market has been expanding. The IGBT has been developed mainly with an emphasis on the improvement of the characteristics in the total loss and the safe operation area. However, in recent years, demands for higher functionality and easier handling have been increasing. In order to meet these various demands, there is a limit in the IGBT alone, and we are trying to respond by making intelligent power devices such as IGBTs. Intelligentization is to integrate power devices and their peripheral circuits to enhance their functions while compensating for their weaknesses. For example, IPM (Intelligent Power Module) has emerged as one of its first Device.

【０００３】このＩＰＭの登場により、従来のサイリス
タやバイポーラトランジスタを用いていた応用分野にＩ
ＧＢＴが急速に浸透するようになった。ＩＧＢＴをイン
バータ等で使用した場合には負荷短絡といつた過電圧、
過電流を印加されるモードがあり、これらをパワーデバ
イス単体での保護の他に、ＩＰＭの技術として外部回路
を通して過熱、過電流、過電圧を検出し、保護を可能と
している例がある。[0003] With the advent of the IPM, the field of application in which conventional thyristors and bipolar transistors have been used has been increased.
GBT became rapidly penetrating. If an IGBT is used in an inverter, etc.
There is a mode in which an overcurrent is applied, and in addition to protection of these by the power device alone, there is an example of enabling protection by detecting overheat, overcurrent, and overvoltage through an external circuit as an IPM technology.

【０００４】図１３に、電流検知部を内蔵型したＩＰＭ
を使用した回路を示す。過電流検知のためには、例えば
ＩＰＭモジュール内に負荷２１への電流制御のための主
ＩＧＢＴ部１３と、電流検知用に分割された補助ＩＧＢ
Ｔ部（以下センスＩＧＢＴ部と称する）１４が内蔵され
ている。このセンスＩＧＢＴ部１４のエミッタ電極と主
ＩＧＢＴ部１３のそれとの間にセンス抵抗３２が接続さ
れ、センスＩＧＢＴ部１４に流れた電流によるセンス抵
抗３２での電圧降下（センス電圧）を検知し、外部保護
回路２０を通じて主ＩＧＢＴ部１３およびセンスＩＧＢ
Ｔ部１４のゲート電圧を低下させるものである。２２は
電源である。FIG. 13 shows an IPM having a built-in current detector.
A circuit using is shown. For overcurrent detection, for example, the main IGBT unit 13 for controlling the current to the load 21 in the IPM module and the auxiliary IGBT divided for current detection.
A T portion (hereinafter referred to as a sense IGBT portion) 14 is built in. A sense resistor 32 is connected between the emitter electrode of the sense IGBT unit 14 and that of the main IGBT unit 13, and a voltage drop (sense voltage) at the sense resistor 32 due to the current flowing in the sense IGBT unit 14 is detected. Through the protection circuit 20, the main IGBT unit 13 and the sense IGBT
The gate voltage of the T section 14 is lowered. 22 is a power supply.

【０００５】図１６に、電流検知部内蔵型ＩＧＢＴを含
むＩＰＭの過電流動作時の信号等のタイミングチャート
を示している。横軸は時間である。（２）の保護回路が
動作していないときは、（１）の制御信号に従ってＩＧ
ＢＴに（３）のゲート信号が与えられ、（４）の出力電
流が流れている。時刻ｔ１に外部状態または素子自身の
事故等によって所定の出力電流以上の過電流が流れる
と、（２）の保護回路が動作し、ＩＧＢＴのゲート信号
（３）が停止され、（４）の出力電流が遮断されて過電
流に対する保護動作が行われたことになる。FIG. 16 shows a timing chart of signals and the like during an overcurrent operation of an IPM including an IGBT with a built-in current detector. The horizontal axis is time. When the protection circuit of (2) is not operating, the IG is controlled according to the control signal of (1).
The gate signal of (3) is given to BT, and the output current of (4) flows. When an overcurrent of a predetermined output current or more flows at time t1 due to an external condition or an accident of the element itself, the protection circuit of (2) operates, the gate signal (3) of the IGBT is stopped, and the output of (4) is output. This means that the current is cut off and the protection operation against overcurrent is performed.

【０００６】時刻ｔ２に（２）の保護回路がリセットさ
れれば、再び（１）の制御信号に従ってＩＧＢＴに
（３）のゲート信号が入力され、時刻ｔ３から（４）の
出力電流が流れ始める。（５）は、（２）の保護回路に
同調して働く、例えばアラーム信号の出力である。図１
７は、電流検知部内蔵型ＩＧＢＴを含むＩＰＭの負荷短
絡時のタイミングチャートを示している。横軸は時間で
ある。（２）の保護回路が動作していないときは、
（１）の制御信号に従ってＩＧＢＴに（３）のゲート信
号が与えられ、（４）の出力電流が流れている。時刻ｔ
１に負荷短絡によって過大な電流が流れると、（２）の
保護回路が動作する。このときは、ＩＧＢＴのゲート信
号（３）を次第に低下させて、（４）の出力電流を遮断
させる。When the protection circuit of (2) is reset at time t2, the gate signal of (3) is input to the IGBT again according to the control signal of (1), and the output current of (4) starts to flow from time t3. . (5) is an output of, for example, an alarm signal that works in synchronization with the protection circuit of (2). FIG.
FIG. 7 shows a timing chart at the time of load short-circuiting of the IPM including the current detection unit built-in IGBT. The horizontal axis is time. When the protection circuit of (2) is not operating,
The gate signal of (3) is given to the IGBT according to the control signal of (1), and the output current of (4) flows. Time t
When an excessive current flows to 1 due to a load short circuit, the protection circuit of (2) operates. At this time, the gate signal (3) of the IGBT is gradually lowered to cut off the output current of (4).

【０００７】時刻ｔ２に（２）の保護回路がリセットさ
れれば、再び（１）の制御信号に従ってＩＧＢＴに
（３）のゲート信号が入力され、時刻ｔ３から（４）の
出力電流が流れ始める。図１４（ａ）に、電流検知部が
半導体素子の一部に内蔵されたＩＰＭの例として、電流
検知部内蔵型ＩＧＢＴのセンスＩＧＢＴ部近傍のゲート
電極中央における水平断面を示す。数ｍｍ角の電流検知
部内蔵型ＩＧＢＴのチップの主ＩＧＢＴ部１３のストラ
イプ状のエミッタ電極８、ゲート電極７の中に、１００
分の１ないし１００００分の１の面積のセンスＩＧＢＴ
部１４が設けられている。センスＩＧＢＴ部１４として
は、酸化膜１８の中に八角形の多結晶シリコンのセンス
ゲート電極２７があり、その中に長い四本のストライプ
状のセンスエミッタ電極２８と短い二本のセンスエミッ
タ電極２８とが見られる。センスエミッタ電極２８とセ
ンスゲート電極２７とは図示されない絶縁膜で絶縁され
ている。図１４（ｂ）は一本のセンスエミッタ電極２８
の下のシリコン基板表面の各拡散領域の拡大平面図であ
る。長環状のｎセンスエミッタ領域２５の中にｐセンス
ウェル領域３０があり、外側にはｐセンスベース領域２
４がある。その外側はｎベース層３である。点線は、セ
ンスエミッタ電極２８の接触範囲を示している。図１４
のストライプ状のセンスエミッタ電極２８の下には全て
同様の拡散領域が形成されている。長環状のｎセンスエ
ミッタ領域２５、ｐセンスベース領域２４、ｐセンスウ
ェル領域３０をセンスエミッタストライプと呼ぶことに
する。When the protection circuit of (2) is reset at time t2, the gate signal of (3) is input to the IGBT again according to the control signal of (1), and the output current of (4) starts to flow from time t3. . FIG. 14A shows a horizontal cross section in the center of the gate electrode in the vicinity of the sense IGBT part of the current detection part built-in IGBT as an example of the IPM in which the current detection part is built in a part of the semiconductor element. 100 mm in the stripe-shaped emitter electrode 8 and gate electrode 7 of the main IGBT part 13 of the current sensing part built-in IGBT chip of several mm square
Sense IGBT with an area of 1 / 10,000 to 1 / 10,000
A section 14 is provided. The sense IGBT section 14 has an octagonal polycrystalline silicon sense gate electrode 27 in an oxide film 18, in which four long stripe-shaped sense emitter electrodes 28 and two short sense emitter electrodes 28 are formed. Can be seen. The sense emitter electrode 28 and the sense gate electrode 27 are insulated by an insulating film (not shown). FIG. 14B shows one sense emitter electrode 28.
FIG. 5 is an enlarged plan view of each diffusion region on the lower silicon substrate surface. There is a p-sense well region 30 in a long ring-shaped n-sense emitter region 25 and a p-sense base region 2 on the outside.
There are four. The outer side is the n base layer 3. The dotted line indicates the contact area of the sense emitter electrode 28. FIG.
Under the stripe-shaped sense emitter electrodes 28, the same diffusion regions are all formed. The ring-shaped n sense emitter region 25, p sense base region 24, and p sense well region 30 will be referred to as a sense emitter stripe.

【０００８】図１５は、図１４のＣ−Ｃ’線に沿った部
分断面図である。図１５の右側部分は、主電流の導通、
遮断のスイッチング作用を行う主ＩＧＢＴ部１３の活性
領域である。図に示したような一つの制御電極を含む単
位の部分（以後セルと呼ぶ）が反転、繰り返しされ、極
めて多数のセルから活性領域は構成されている。また、
ＩＧＢＴの周縁部分には、ガードリング構造やフィール
ドプレート構造のような耐圧構造が設けられているが、
図には示していない。FIG. 15 is a partial sectional view taken along the line CC 'of FIG. The right part of FIG. 15 shows the conduction of the main current,
This is an active region of the main IGBT portion 13 that performs a switching operation of interruption. As shown in the figure, a unit portion including one control electrode (hereinafter referred to as a cell) is inverted and repeated, and an active region is composed of an extremely large number of cells. Also,
Although a withstand voltage structure such as a guard ring structure or a field plate structure is provided in the peripheral portion of the IGBT,
Not shown in the figure.

【０００９】主ＩＧＢＴ部１３は、ｐコレクタ層１の上
にｎ⁺バッファ層２を介して積層されたｎベース層３の
表面層に選択的にｐベース領域４が形成され、そのｐベ
ース領域４の一部に拡散深さの深いｐウェル領域１０が
形成されている。ｐベース領域４の表面層にはまた選択
的にｎエミッタ領域５が形成されている。ｎベース層３
とｎエミッタ領域５に挟まれたｐベース領域４の表面上
に、ゲート酸化膜６を介して、多結晶シリコンからなり
Ｇ端子に接続されるゲート電極７が設けられている。ま
た、ｐコレクタ層１の裏面にはＣ端子に接続されるコレ
クタ電極９が、ｎエミッタ領域５の上にはｎエミッタ領
域５とｐベース領域４に共通に接触しＥ端子に接続され
るエミッタ電極８がそれぞれ設けられている。このＩＧ
ＢＴは、ゲート酸化膜６、ゲート電極７、ｐベース領域
４、ｎエミッタ領域５、ｎベース層３、ｎ⁺バッファ層
２で構成されるＭＯＳＦＥＴとｐコレクタ層１、ｎ⁺バ
ッファ層２、ｎベース層３、ｐベース領域４、で構成さ
れているｐｎｐトランジスタとからなるものとみること
もできる。In the main IGBT portion 13, a p base region 4 is selectively formed in the surface layer of an n base layer 3 laminated on the p collector layer 1 with an n ⁺ buffer layer 2 interposed therebetween. A p-well region 10 having a large diffusion depth is formed in a part of 4. An n emitter region 5 is selectively formed on the surface layer of the p base region 4. n base layer 3
A gate electrode 7 made of polycrystalline silicon and connected to the G terminal is provided on the surface of the p base region 4 sandwiched between the n emitter region 5 and the n emitter region 5. A collector electrode 9 connected to the C terminal is provided on the back surface of the p collector layer 1, and an emitter connected to the E terminal in contact with the n emitter region 5 and the p base region 4 on the n emitter region 5. Electrodes 8 are provided, respectively. This IG
BT is a MOSFET composed of a gate oxide film 6, a gate electrode 7, a p base region 4, an n emitter region 5, an n base layer 3 and an n ⁺ buffer layer 2 and a p collector layer 1, an n ⁺ buffer layer 2 and n. It can also be regarded as consisting of a pnp transistor composed of the base layer 3 and the p base region 4.

【００１０】図１５の左側部に、電流検知部として、セ
ンスＩＧＢＴ部１４が設けられている。センスＩＧＢＴ
部１４は上記説明の主ＩＧＢＴと同時に形成されてい
る。すなわち、ｐコレクタ層１、ｎ⁺バッファ層２とｎ
ベース層３は共通であり、そのｎベース層３の表面層に
選択的にｐセンスベース領域２４が形成されている。ｐ
センスベース領域２４の周囲には広いｐ分離領域１６が
形成されている。ｐセンスベース領域２４の表面層に選
択的にｎセンスエミッタ領域２５が形成され、ｎベース
層３とｎセンスエミッタ領域２５に挟まれたｐセンスベ
ース領域２４の表面上にセンスゲート酸化膜２６を介し
て多結晶シリコンからなるセンスゲート電極２７が設け
られている。また、ｎセンスエミッタ領域２５とｐセン
スベース領域２４に共通に接触し、ＳＥ端子に接続され
るセンスエミッタ電極２８がそれぞれ設けられている。
図１４ではセンスエミッタ電極２８がストライプ状であ
ったが、断面図に見られるように、絶縁膜１５を挟んで
センスゲート電極２７上で接続しているのである。ｎベ
ース層３以下、ｐコレクタ層１の裏面のＣ端子に接続さ
れるコレクタ電極１１までは主ＩＧＢＴ部１３と共通で
ある。センスゲート電極２７は図示されない断面で主Ｉ
ＧＢＴ部１３のゲート電極７と接続されている。センス
エミッタ電極２８はセンス抵抗３２を介してエミッタ電
極８に接続される。図ではセンス抵抗３２は外付けの抵
抗としたが、半導体チップ内部に構成することもでき
る。On the left side of FIG. 15, a sense IGBT section 14 is provided as a current detecting section. Sense IGBT
The portion 14 is formed at the same time as the main IGBT described above. That is, p collector layer 1, n ⁺ buffer layer 2 and n
The base layer 3 is common, and the p-sense base region 24 is selectively formed in the surface layer of the n base layer 3. p
A wide p isolation region 16 is formed around the sense base region 24. An n sense emitter region 25 is selectively formed in the surface layer of the p sense base region 24, and a sense gate oxide film 26 is formed on the surface of the p sense base region 24 sandwiched between the n base layer 3 and the n sense emitter region 25. A sense gate electrode 27 made of polycrystalline silicon is provided therethrough. Further, a sense emitter electrode 28 that is in common contact with the n-sense emitter region 25 and the p-sense base region 24 and is connected to the SE terminal is provided.
In FIG. 14, the sense emitter electrode 28 has a stripe shape, but as shown in the cross-sectional view, the sense emitter electrode 28 is connected on the sense gate electrode 27 with the insulating film 15 interposed therebetween. The n base layer 3 and the layers up to the collector electrode 11 connected to the C terminal on the back surface of the p collector layer 1 are common to the main IGBT portion 13. The sense gate electrode 27 has a main I
It is connected to the gate electrode 7 of the GBT portion 13. The sense emitter electrode 28 is connected to the emitter electrode 8 via the sense resistor 32. Although the sense resistor 32 is an external resistor in the figure, it may be formed inside the semiconductor chip.

【００１１】図１５の中央部には、ｎベース層３の表面
層にｐベース領域４と一部が重複するようにｐ引き抜き
領域１９が形成されている。このｐ引き抜き領域１９
は、表面上にエミッタ電極８が接触しており、オフ動作
時に主ＩＧＢＴ部１３とセンスＩＧＢＴ部１４の境界部
分のｎベース層３内の正孔を引き抜くためのものであ
る。At the center of FIG. 15, a p-pull-out region 19 is formed in the surface layer of the n-base layer 3 so as to partially overlap the p-base region 4. This p extraction region 19
Is for extracting the holes in the n-base layer 3 at the boundary portion between the main IGBT portion 13 and the sense IGBT portion 14 at the time of the OFF operation because the emitter electrode 8 is in contact with the surface.

【００１２】このＩＧＢＴのスイッチング動作は次のよ
うに行う。Ｃ端子に、Ｅ端子に対して正の電圧を印加し
た状態で、ゲート電極７にしきい値以上の電圧を印加す
ることによって、ゲート電極７の直下のｐベース領域４
の表面層（チャネル領域１１）に反転層が形成され、前
記ＭＯＳＦＥＴが導通する。その反転層を通ってｎエミ
ッタ領域５から電子がｎベース層３、ｎ⁺バッファ層２
に注入される。ｐコレクタ層１とｎ⁺バッファ層２との
間の接合は順バイアスされているので、電子がこの接合
を通ってｐコレクタ層１に流入する。すると、ｐコレク
タ層１、ｎ⁺バッファ層２とｎベース層３、ｐベース領
域４をそれぞれエミッタ、ベース、コレクタとするｐｎ
ｐトランジスタが動作し、伝導度変調を発生して主ＩＧ
ＢＴ部１３がオンする。図２７に、定格電流１５０Ａ、
電圧６００ＶのＩＧＢＴの電流−電圧特性を示した。横
軸はコレクタ−エミッタ間電圧Ｖ_CE、たて軸はコレクタ
電流Ｉ_Cである。伝導度変調を利用しているので、オン
電圧が小さいことがわかる。The switching operation of this IGBT is performed as follows. By applying a voltage equal to or higher than a threshold value to the gate electrode 7 in a state where a positive voltage is applied to the C terminal with respect to the E terminal, the p base region 4 immediately below the gate electrode 7 is applied.
An inversion layer is formed on the surface layer (channel region 11) of the above, and the MOSFET becomes conductive. Electrons from the n emitter region 5 pass through the inversion layer to the n base layer 3 and the n ⁺ buffer layer 2.
Is injected into. Since the junction between the p collector layer 1 and the n ⁺ buffer layer 2 is forward biased, electrons flow into the p collector layer 1 through this junction. Then, the pn having the p collector layer 1 and the n ⁺ buffer layer 2 and the n base layer 3 and the p base region 4 as the emitter, the base and the collector, respectively.
The p-transistor operates to generate conductivity modulation, and the main IG
The BT unit 13 turns on. FIG. 27 shows a rated current of 150 A,
The current-voltage characteristics of the IGBT having a voltage of 600 V are shown. The horizontal axis represents the collector-emitter voltage V _CE , and the vertical axis represents the collector current I _C. It can be seen that the on-voltage is small because the conductivity modulation is used.

【００１３】センスＩＧＢＴ部１４は主ＩＧＢＴ部１３
と並列に形成されているので、センスゲート電極２７に
しきい値以上の電圧を印加することによって、同様にセ
ンスゲート電極２７の直下のｐセンスベース領域２４の
表面層（センスチャネル領域３１）に反転層が形成さ
れ、その反転層を通ってｎセンスエミッタ領域２５から
電子がｎベース層３、ｎ⁺バッファ層２に注入される。
ｐコレクタ層１とｎ⁺バッファ層２との間の接合は順バ
イアスされているので、電子がこの接合を通ってｐコレ
クタ層１に流入する。すると、ｐコレクタ層１、ｎ⁺バ
ッファ層２とｎベース層３、ｐセンスベース領域２４を
それぞれエミッタ、ベース、コレクタとするｐｎｐトラ
ンジスタが動作し、伝導度変調を発生してセンスＩＧＢ
Ｔ部１４がオンする。そのセンスＩＧＢＴ部１４に分流
する電流によって、センス抵抗３２に電圧降下を生じ
る。過電流が流れたときは、そのセンス抵抗３２におけ
る電圧降下が増大するので、そのセンス電圧を図示され
ない保護回路で処理し、主ＩＧＢＴ部１３およびセンス
ＩＧＢＴ部１４のゲート電圧を低下させ、半導体素子、
および回路を保護するものである。The sense IGBT unit 14 is the main IGBT unit 13.
Since it is formed in parallel with the sensor gate electrode 27, it is inverted to the surface layer (sense channel region 31) of the p-sense base region 24 immediately below the sense gate electrode 27 by applying a voltage equal to or higher than the threshold value to the sense gate electrode 27. A layer is formed, and electrons are injected into the n base layer 3 and the n ⁺ buffer layer 2 from the n sense emitter region 25 through the inversion layer.
Since the junction between the p collector layer 1 and the n ⁺ buffer layer 2 is forward biased, electrons flow into the p collector layer 1 through this junction. Then, the pnp transistor having the p collector layer 1, the n ⁺ buffer layer 2 and the n base layer 3, and the p sense base region 24 as the emitter, the base, and the collector operates to generate the conductivity modulation and generate the sense IGB.
The T section 14 is turned on. Due to the current shunting to the sense IGBT unit 14, a voltage drop occurs in the sense resistor 32. When an overcurrent flows, the voltage drop in the sense resistor 32 increases. Therefore, the sense voltage is processed by a protection circuit (not shown) to reduce the gate voltage of the main IGBT section 13 and the sense IGBT section 14, and the semiconductor element ,
And to protect the circuit.

【００１４】このＩＧＢＴをオフする場合は、ゲート電
極７およびセンスゲート電極２７の電圧を除くことによ
って、ゲート電極７およびセンスゲート電極２７直下の
ｐベース領域４、ｐセンスベース領域２４の表面層に形
成されていた反転層が消滅し、ｎエミッタ領域５および
ｎセンスエミッタ領域２５からの電子の注入が止まりオ
フする。When the IGBT is turned off, by removing the voltages of the gate electrode 7 and the sense gate electrode 27, the surface layers of the p base region 4 and the p sense base region 24 immediately below the gate electrode 7 and the sense gate electrode 27 are removed. The formed inversion layer disappears, the injection of electrons from the n emitter region 5 and the n sense emitter region 25 is stopped, and the inversion layer is turned off.

【００１５】[0015]

【発明が解決しようとする課題】図１８は、他の保護回
路の例である。この例では、センス抵抗が、過電流用セ
ンス抵抗３２ａと負荷短絡用センス抵抗３２ｂに分けら
れていて、それぞれ保護回路２０の端子に接続されてい
る。このようにすれば、過電流時と負荷短絡時の対応を
変えることができ、例えば負荷短絡時に保護回路２０に
入力されるセンス電圧が過大になるのが避けられる。FIG. 18 is an example of another protection circuit. In this example, the sense resistor is divided into an overcurrent sense resistor 32a and a load short-circuit sense resistor 32b, each of which is connected to a terminal of the protection circuit 20. In this way, the correspondence between overcurrent and load short-circuit can be changed, and for example, the sense voltage input to the protection circuit 20 at the time of load short-circuit can be prevented from becoming excessive.

【００１６】図１９（ａ）、（ｂ）に、従来の電流検知
部内蔵型ＩＧＢＴの負荷短絡時の電流、電圧波形を示
す。図１９（ｂ）は、図１８のように過電流用センス抵
抗３２ａと負荷短絡用センス抵抗３２ｂに分けたとき、
同図（ａ）は分けなかったときの波形である。同図
（ｂ）では負荷短絡用センス抵抗３２ｂとして小さい抵
抗を用いているので、コレクタ電流は低い値に抑えられ
ている。しかしいずれの場合も負荷短絡時の電流検知部
内蔵型ＩＧＢＴの動作は、図１９に示したように安定し
ていることがわかる。この理由は、図１４に示したよう
に、主ＩＧＢＴ部からセンスＩＧＢＴ部が十分隔離され
ているからである。負荷短絡時には図１９に示す電流、
電圧が主ＩＧＢＴ部、センスＩＧＢＴ部に印加される
が、このとき、センスＩＧＢＴ部においては、主ＩＧＢ
Ｔ部がオンしている際に発生する正孔の回り込みを、主
ＩＧＢＴ部からセンスＩＧＢＴ部を十分隔離することに
よって抑制し、短絡時の制限電流値を安定させているの
である。19 (a) and 19 (b) show current and voltage waveforms of a conventional IGBT with a built-in current detector when a load is short-circuited. 19B is divided into an overcurrent sense resistor 32a and a load short-circuit sense resistor 32b as shown in FIG.
FIG. 7A shows the waveform when the division is not made. Since a small resistor is used as the load short-circuiting sense resistor 32b in FIG. 8B, the collector current is suppressed to a low value. However, in any case, it is understood that the operation of the current detection unit built-in IGBT at the time of load short circuit is stable as shown in FIG. This is because, as shown in FIG. 14, the sense IGBT section is sufficiently isolated from the main IGBT section. When the load is short-circuited, the current shown in Fig. 19,
A voltage is applied to the main IGBT section and the sense IGBT section. At this time, in the sense IGBT section, the main IGBT section is
The sneak of holes generated when the T section is turned on is suppressed by sufficiently separating the sense IGBT section from the main IGBT section, and the limiting current value at the time of short circuit is stabilized.

【００１７】しかし、過電流時の保護動作、特に高温で
の動作が不安定であることがわかった。図２０に、２５
℃、１２５℃でのセンス電圧のセンス抵抗依存性を示
す。横軸はセンス抵抗（Ｒ_S）、縦軸はセンス電圧（Ｖ
_S）である。このセンス電圧は定格電流の２倍の電流を
流したときのセンス抵抗での電圧降下である。高温での
センス電圧の曲線には折れ曲がりが見られ、低いセンス
抵抗範囲での温度依存性が、高いセンス抵抗範囲での温
度依存性よりかなり大きい。このことは、特に低いセン
ス抵抗範囲で、保護回路が動作する電圧降下（センス電
圧Ｖ_S）を決めるとき問題になる。例えば、２５℃で保
護回路が動作する電流を設定したとき、１２５℃では遙
かに少ない電流で保護回路が動作してしまうことになる
からである。However, it has been found that the protection operation at the time of overcurrent, especially the operation at high temperature, is unstable. In FIG. 20, 25
The dependence of the sense voltage on the sense resistance at ℃ and 125 ℃ is shown. The horizontal axis represents the sense resistance (R _S ) and the vertical axis represents the sense voltage (V
_S ). This sense voltage is a voltage drop across the sense resistor when a current twice the rated current is passed. The curve of the sense voltage at high temperature shows a bend, and the temperature dependence in the low sense resistance range is considerably larger than that in the high sense resistance range. This is particularly a low sense resistance range, the protection circuit becomes a problem when determining the voltage drop to operate (sense voltage V _S). This is because, for example, when the current at which the protection circuit operates at 25 ° C. is set, the protection circuit operates at a much smaller current at 125 ° C.

【００１８】この温度依存性の不連続になる原因究明の
ため、センスＩＧＢＴの特性を調べた。図２１に、セン
スＩＧＢＴの電流−電圧特性を示す。横軸は電圧
（Ｖ_CE）、縦軸は電流（Ｉ_c）である。２５℃、１２５
℃共に負性抵抗領域があること、また、負性抵抗領域が
始まる電圧が、２５℃と１２５℃とでずれていることが
わかる。すなわち、センスＩＧＢＴの動作抵抗（Ｒｏ
ｎ）が２５℃と１２５℃でずれることによって、過電流
時のセンス電圧の温度依存性が悪化することが明らかに
なった。The characteristics of the sense IGBT were examined in order to investigate the cause of this temperature-dependent discontinuity. FIG. 21 shows the current-voltage characteristic of the sense IGBT. The horizontal axis represents voltage (V _CE ) and the vertical axis represents current (I _c ). 25 ° C, 125
It can be seen that there is a negative resistance region at both ° C and that the voltage at which the negative resistance region starts differs between 25 ° C and 125 ° C. That is, the operating resistance of the sense IGBT (Ro
It was revealed that the temperature dependency of the sense voltage at the time of overcurrent is deteriorated by the difference of n) between 25 ° C and 125 ° C.

【００１９】以上の問題に鑑み、本発明の目的は過電流
検知精度の高い電流検知部を内蔵する絶縁ゲートバイポ
ーラトランジスタを提供することにある。In view of the above problems, it is an object of the present invention to provide an insulated gate bipolar transistor having a built-in current detection section with high overcurrent detection accuracy.

【００２０】[0020]

【課題を解決するための手段】上記課題解決のため本発
明は、第一導電型半導体層と、その第一導電型半導体層
の一方の側の表面層に選択的に形成された第二導電型ベ
ース領域と、その第二導電型ベース領域の表面層に選択
的に形成された第一導電型エミッタ領域と、第二導電型
ベース領域の第一導電型半導体層と第一導電型エミッタ
領域に挟まれた部分であるチャネル領域の表面上にゲー
ト絶縁膜を介して形成されたゲート電極と、チャネル領
域以外の第二導電型ベース領域および第一導電型エミッ
タ領域の表面上に共通に接触するエミッタ電極と、第一
導電型半導体層の表面層の別の部分に形成された第二導
電型コレクタ領域と、その第二導電型コレクタ領域の表
面に接触して設けられたコレクタ電極と、第一導電型半
導体層の一方の側の表面層の別の部分に第二導電型ベー
ス領域と一部を重複して形成され、表面上にエミッタ電
極が接触している第二導電型引き抜き領域とからなる主
ＩＧＢＴ部と、第一導電型半導体層以下の部分を主ＩＧ
ＢＴ部と共通にし、第一導電型半導体層の表面層の第二
導電型引き抜き領域に隣接した領域に形成された第二導
電型センスベース領域、その第二導電型センスベース領
域の表面層に選択的に形成された第一導電型センスエミ
ッタ領域と、第二導電型センスベース領域の第一導電型
半導体層と第一導電型センスエミッタ領域に挟まれた部
分であるセンスチャネル領域の表面上にセンスゲート絶
縁膜を介して形成されたセンスゲート電極と、センスチ
ャネル領域以外の第二導電型センスベース領域および第
一導電型センスエミッタ領域の表面上に共通に接触する
センスエミッタ電極とからなる電流検知のためのセンス
ＩＧＢＴ部とを有し、エミッタ電極とセンスエミッタ電
極との間に接続されたセンス抵抗での電圧降下を利用す
る電流検知部内蔵型絶縁ゲートバイポーラトランジスタ
において、保護のため検知すべき電流水準における主Ｉ
ＧＢＴ部のオン電圧以下の範囲で、センスＩＧＢＴ部の
電流−電圧特性が線型であるものとする。To solve the above problems, the present invention provides a first conductivity type semiconductor layer and a second conductivity type selectively formed on a surface layer on one side of the first conductivity type semiconductor layer. Type base region, a first conductivity type emitter region selectively formed in a surface layer of the second conductivity type base region, a first conductivity type semiconductor layer and a first conductivity type emitter region of the second conductivity type base region The gate electrode formed on the surface of the channel region, which is the part sandwiched by the gate electrode, via the gate insulating film, and the surface of the second conductivity type base region and the first conductivity type emitter region other than the channel region are commonly contacted. An emitter electrode, a second conductivity type collector region formed in another portion of the surface layer of the first conductivity type semiconductor layer, and a collector electrode provided in contact with the surface of the second conductivity type collector region, One side of the first conductivity type semiconductor layer A main IGBT part, which is formed in another portion of the surface layer so as to partially overlap with the second conductivity type base region and has a second conductivity type extraction region in contact with the emitter electrode on the surface, and a first conductivity type Type IG
A second conductivity type sense base region formed in a region adjacent to the second conductivity type extraction region of the surface layer of the first conductivity type semiconductor layer in common with the BT portion, and a surface layer of the second conductivity type sense base region. On the surface of the sense channel region, which is a portion sandwiched between the first conductivity type sense emitter region selectively formed and the first conductivity type semiconductor layer of the second conductivity type sense base region and the first conductivity type sense emitter region. A sense gate electrode formed via a sense gate insulating film, and a sense emitter electrode commonly contacting the surfaces of the second conductivity type sense base region and the first conductivity type sense emitter region other than the sense channel region. Built-in current detection unit having a sense IGBT unit for current detection and utilizing a voltage drop in a sense resistor connected between an emitter electrode and a sense emitter electrode In the insulated gate bipolar transistor, the main in the current levels to be detected for protection I
It is assumed that the current-voltage characteristic of the sense IGBT unit is linear in the range equal to or lower than the ON voltage of the GBT unit.

【００２１】センスＩＧＢＴ部の電流−電圧特性が線型
であれば、センス抵抗での電圧降下に不連続点を生じな
い。そして、センス電圧の温度依存性が安定する。セン
スＩＧＢＴ部の電流−電圧特性が線型であるためには、
第二導電型センスベース領域が一本のストライプ状であ
るものが良い。センスＩＧＢＴ部のゲート幅が主ＩＧＢ
Ｔ部のゲート幅に比べて狭いものでもよく、また、セン
スＩＧＢＴ部のしきい値が主ＩＧＢＴ部のゲートのしき
い値に対し高いものでもよい。センスＩＧＢＴ部のしき
い値を高めるには、第二導電型センスベース領域の表面
不純物濃度が主ＩＧＢＴ部の第二導電型ベース領域のそ
れより高いようにすればよい。If the current-voltage characteristic of the sense IGBT section is linear, no discontinuity occurs in the voltage drop across the sense resistor. Then, the temperature dependence of the sense voltage becomes stable. In order for the current-voltage characteristic of the sense IGBT unit to be linear,
It is preferable that the second conductivity type sense base region is in the form of one stripe. The gate width of the sense IGBT section is the main IGBT
It may be narrower than the gate width of the T section, or the threshold of the sense IGBT section may be higher than the threshold of the gate of the main IGBT section. In order to increase the threshold value of the sense IGBT portion, the surface impurity concentration of the second conductivity type sense base region may be set higher than that of the second conductivity type base region of the main IGBT portion.

【００２２】第二導電型センスベース領域が一本のスト
ライプ状であれば、その表面層の第一導電型センスエミ
ッタ領域から注入される第一導電型キャリア量が少な
く、第二導電型コレクタ層から注入される第二導電型ベ
ース層キャリア量も少なくなって、伝導度変調が起きに
くい。センスＩＧＢＴ部のゲート幅を主ＩＧＢＴ部のゲ
ート幅に比べて狭いものとすれば、接合型ＦＥＴ効果に
よって、第二導電型ベース領域間をキャリアが通過する
際の抵抗分が増し、やはり伝導度変調が起きにくくな
る。第二導電型センスベース領域の表面不純物濃度を高
めるなどして、センスＩＧＢＴ部のゲートのしきい値を
主ＩＧＢＴ部のゲートのしきい値に比べて高くすれば、
センスＩＧＢＴ部のゲート電極にかかる実効的な電圧が
低くなり、チャネル領域の抵抗が増して第一導電型セン
スエミッタ領域から注入される第一導電型キャリア量が
少なくなり、やはり伝導度変調が起きにくくなる。If the second-conductivity-type sense base region has one stripe shape, the amount of the first-conductivity-type carriers injected from the first-conductivity-type sense emitter region of the surface layer is small, and the second-conductivity-type collector layer. The amount of carriers of the second conductivity type base layer injected from is also small, and conductivity modulation is less likely to occur. If the gate width of the sense IGBT portion is made narrower than the gate width of the main IGBT portion, the junction FET effect increases the resistance when carriers pass between the second conductivity type base regions, and the conductivity is also increased. Modulation is less likely to occur. By increasing the surface impurity concentration of the second conductivity type sense base region and making the threshold value of the gate of the sense IGBT section higher than the threshold value of the gate of the main IGBT section,
The effective voltage applied to the gate electrode of the sense IGBT portion is lowered, the resistance of the channel region is increased, and the amount of carriers of the first conductivity type injected from the sense emitter region of the first conductivity type is decreased, which also causes conductivity modulation. It gets harder.

【００２３】センスチャネル領域を主セル部のチャネル
領域よりも長くすること、センスゲート酸化膜上に部分
的に厚い酸化膜が形成すること、第一導電型センスエミ
ッタ領域を選択的に形成することによっても、センスＩ
ＧＢＴ部の電流−電圧特性が線型に近くなる。センスチ
ャネル領域のチャネル長が長くなれば、チャネル抵抗が
増し、センスゲート酸化膜上に部分的に厚い酸化膜を形
成すれば、その下のチャネル領域が薄くなり、第一導電
型センスエミッタ領域を選択的に形成すれば、第一導電
型センスエミッタ領域の面積が減少して、いずれも第一
導電型センスエミッタ領域からの第一導電型キャリアの
注入量を低下させる。To make the sense channel region longer than the channel region of the main cell portion, to partially form a thick oxide film on the sense gate oxide film, and to selectively form the first conductivity type sense emitter region. By sense i
The current-voltage characteristic of the GBT part becomes close to linear. If the channel length of the sense channel region is increased, the channel resistance is increased, and if a thick oxide film is partially formed on the sense gate oxide film, the channel region below it is thinned, and the first conductivity type sense emitter region is formed. If selectively formed, the area of the first-conductivity-type sense emitter region is reduced, and in both cases, the injection amount of the first-conductivity-type carriers from the first-conductivity-type sense emitter region is reduced.

【００２４】更に、第二導電型センスベース領域上に分
離電極を形成し、主ＩＧＢＴ部のエミッタ電極と接続す
ることもよい。そのようにすれば、第一導電型センスエ
ミッタ領域からセンス抵抗に流れる電流は第一導電型キ
ャリアの電流のみとなり、センスＩＧＢＴはＭＯＳＦＥ
Ｔに近い動作をするようになる。Further, a separation electrode may be formed on the second conductivity type sense base region and connected to the emitter electrode of the main IGBT portion. By doing so, the current flowing from the first-conductivity-type sense emitter region to the sense resistor is only the current of the first-conductivity-type carrier, and the sense IGBT is MOSFE.
It comes to behave like T.

【００２５】電流検知のためのセンスＩＧＢＴを有する
電流検知部内蔵型ＩＧＢＴにおいて、エミッタ電極とセ
ンスエミッタ電極との間にダイオードを接続することも
よい。そのようにすれば、センスＩＧＢＴのゲートにか
かる実効的なゲート電圧がダイオードの順電圧分だけ低
下する。従って、チャネル領域の抵抗が増して第一導電
型センスエミッタ領域から注入される第一導電型キャリ
ア量が少なくなり、やはり伝導度変調が起きにくくな
る。In a current detection section built-in IGBT having a sense IGBT for current detection, a diode may be connected between the emitter electrode and the sense emitter electrode. By doing so, the effective gate voltage applied to the gate of the sense IGBT is reduced by the forward voltage of the diode. Therefore, the resistance of the channel region is increased, the amount of the first conductivity type carriers injected from the first conductivity type sense emitter region is reduced, and conductivity modulation is less likely to occur.

【００２６】ダイオードがチップ上に形成され、そのダ
イオードの第二導電型アノード領域をセンスエミッタ電
極と接続したものとすることもできる。そのようにすれ
ば、ダイオードを外付けする必要がなく、また小型化で
きる。It is also possible that a diode is formed on the chip and the second conductivity type anode region of the diode is connected to the sense emitter electrode. By doing so, it is not necessary to attach a diode externally, and the size can be reduced.

【００２７】[0027]

【発明の実施の形態】以下図面を参照しながら、本発明
の実施の形態について説明する。尚、以下でｐ、ｎを冠
した層、領域等はそれぞれ正孔、電子が多数キャリアで
ある層、領域等を意味する。〔実施例１〕図１派、本発明第一の実施例の電流検知部
内蔵型ＩＧＢＴのセンスＩＧＢＴ部１４近傍のゲート電
極中央における水平断面図である。主ＩＧＢＴ部１３の
ストライプ状のエミッタ電極８、ゲート電極７に取り囲
まれて、広いｐ分離領域上の酸化膜１８があり、その中
央部に八角形のゲート電極２７が見られる。図１４の従
来例との違いは、センスＩＧＢＴ部１４が一本のセンス
エミッタストライプを有することである。従って、この
断面図では一本のストライプ状のセンスエミッタ電極２
８が見られるだけである。センスエミッタ電極２８とセ
ンスゲート電極２７とは図示されない絶縁膜で絶縁され
ている。八角形のセンスゲート電極２７から図の下方に
延びている帯はセンスゲート電極２７と主ＩＧＢＴ部１
３のゲート電極７とを結ぶ連結部である。なお、この連
結部の下にも後出のｐ分離領域が形成されている。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In the following, layers, regions, etc. bearing p and n mean layers, regions, etc., in which holes and electrons are majority carriers, respectively. [Embodiment 1] FIG. 1 is a horizontal sectional view in the center of a gate electrode in the vicinity of a sense IGBT portion 14 of a current detection portion built-in type IGBT according to a first embodiment of the present invention. Surrounded by the striped emitter electrode 8 and the gate electrode 7 of the main IGBT portion 13, there is an oxide film 18 on a wide p isolation region, and an octagonal gate electrode 27 is seen in the central portion. The difference from the conventional example of FIG. 14 is that the sense IGBT section 14 has one sense emitter stripe. Therefore, in this sectional view, one stripe-shaped sense emitter electrode 2 is formed.
Only 8 can be seen. The sense emitter electrode 28 and the sense gate electrode 27 are insulated by an insulating film (not shown). The band extending downward from the octagonal sense gate electrode 27 in the drawing is the sense gate electrode 27 and the main IGBT portion 1.
3 is a connecting portion that connects the gate electrode 7 of FIG. Note that a p isolation region, which will be described later, is also formed under the connecting portion.

【００２８】図３に、図１のＡ−Ａ’線に沿った部分断
面を示す。図の右側部分は、電流検知部内蔵型ＩＧＢＴ
の主電流の導通、遮断のスイッチング作用を行う主ＩＧ
ＢＴ部１３の活性領域である。図１４の従来例と同じ
く、ｐコレクタ層１の上にｎ⁺バッファ層２を介して積
層されたｎベース層３の表面層に選択的にｐベース領域
４および一部に拡散深さの深いｐウェル領域１０が形成
されている。そのｐベース領域４の表面層に選択的にｎ
エミッタ領域５が形成され、ｎベース層３とｎエミッタ
領域５に挟まれたｐベース領域４の表面上に、ゲート酸
化膜６を介して、多結晶シリコンからなりＧ端子に接続
されるゲート電極７が設けられている。また、ｐコレク
タ層１の裏面にはＣ端子に接続されるコレクタ電極９
が、ｎエミッタ領域５の上にはｎエミッタ領域５とｐウ
ェル領域１０の表面に共通に接触しＥ端子に接続される
エミッタ電極８がそれぞれ設けられている。FIG. 3 shows a partial cross section taken along the line AA 'in FIG. The right part of the figure is an IGBT with a built-in current detector.
Main IG that conducts switching operation for main current conduction and interruption
It is an active region of the BT portion 13. As in the conventional example shown in FIG. 14, the surface layer of the n base layer 3 laminated on the p collector layer 1 via the n ⁺ buffer layer 2 is selectively deep in the p base region 4 and a part thereof. A p-well region 10 is formed. Selectively n on the surface layer of the p base region 4.
A gate electrode formed of polycrystalline silicon on the surface of the p base region 4 sandwiched between the n base layer 3 and the n emitter region 5 in which the emitter region 5 is formed and made of polycrystalline silicon and connected to the G terminal. 7 is provided. In addition, a collector electrode 9 connected to the C terminal is formed on the back surface of the p collector layer 1.
However, on the n-emitter region 5, there are provided emitter electrodes 8 that are in common contact with the surfaces of the n-emitter region 5 and the p-well region 10 and are connected to the E terminal.

【００２９】このようなＩＧＢＴのｎベース層３は、例
えば、ｐコレクタ層１とその上に積層されたｎ⁺バッフ
ァ層２とからなるサブストレート上にエピタキシャル成
長により形成される。またｐベース領域４は、まず先に
形成したゲート電極７をマスクとした不純物の導入によ
り形成され、ｎエミッタ領域５は、図示されていないフ
ォトレジストをマスクとしての不純物の導入により形成
される。図のようにゲート電極７の上に、絶縁膜１５を
介してエミッタ電極８を延長してもよい。The n base layer 3 of such an IGBT is formed, for example, by epitaxial growth on a substrate composed of the p collector layer 1 and the n ⁺ buffer layer 2 laminated thereon. Further, p base region 4 is formed by introducing impurities using the gate electrode 7 formed earlier as a mask, and n emitter region 5 is formed by introducing impurities using a photoresist (not shown) as a mask. As shown in the figure, the emitter electrode 8 may be extended on the gate electrode 7 via the insulating film 15.

【００３０】図３の左側部には、電流検知部として、セ
ンスＩＧＢＴ部１４が設けられている。センスＩＧＢＴ
部１４は上記説明の主ＩＧＢＴ部１３と同時に形成され
る。すなわち、ｐコレクタ層１、ｎ⁺バッファ層２とｎ
ベース層３は主ＩＧＢＴ部１３と共通であり、そのｎベ
ース層３の表面層に選択的にｐセンスベース領域２４お
よび一部に拡散深さの深いｐセンスウェル領域３０が形
成されている。そのｐセンスベース領域２４の表面層に
選択的にｎセンスエミッタ領域２５が形成され、ｎベー
ス層３とｎセンスエミッタ領域２５に挟まれたｐセンス
ベース領域２４の表面上にセンスゲート酸化膜２６を介
して多結晶シリコンからなるセンスゲート電極２７が設
けられている。また、ｎセンスエミッタ領域２５とｐセ
ンスウェル領域３０に共通に接触し、ＳＥ端子に接続さ
れるセンスエミッタ電極２８が設けられている。ｐセン
スベース領域２４の外側には、広いｐ分離領域１６があ
り、その上は酸化膜１８で覆われている。センスゲート
電極２７と主ＩＧＢＴ部１３のゲート電極７とは図示さ
れない部分で接続されている。On the left side of FIG. 3, a sense IGBT section 14 is provided as a current detecting section. Sense IGBT
The portion 14 is formed at the same time as the main IGBT portion 13 described above. That is, p collector layer 1, n ⁺ buffer layer 2 and n
The base layer 3 is also common to the main IGBT portion 13, and a p sense base region 24 and a p sense well region 30 having a deep diffusion depth are selectively formed in the surface layer of the n base layer 3. An n sense emitter region 25 is selectively formed on the surface layer of the p sense base region 24, and a sense gate oxide film 26 is formed on the surface of the p sense base region 24 sandwiched between the n base layer 3 and the n sense emitter region 25. A sense gate electrode 27 made of polycrystalline silicon is provided via the. Further, a sense emitter electrode 28, which is in common contact with the n sense emitter region 25 and the p sense well region 30 and is connected to the SE terminal, is provided. A wide p isolation region 16 is provided outside the p sense base region 24, and an oxide film 18 covers the p isolation region 16. The sense gate electrode 27 and the gate electrode 7 of the main IGBT portion 13 are connected at a portion not shown.

【００３１】センスエミッタ電極２８はセンス抵抗３２
を通じて主エミッタ電極８に接続される。図ではセンス
抵抗３２は外付けの抵抗としたが、半導体素子内部に構
成することもできる。図３の中央部には、ｎベース層の
表面層にｐベース領域４と一部が重複するようにｐ引き
抜き領域１９が形成されている。このｐ引き抜き領域１
９は、表面上にエミッタ電極８が接触しており、オフ動
作時に主ＩＧＢＴ部１３とセンスＩＧＢＴ部１４の境界
部分のｎベース層３内の正孔を引き抜くためのものであ
る。The sense emitter electrode 28 is a sense resistor 32.
Through to the main emitter electrode 8. Although the sense resistor 32 is an external resistor in the drawing, it may be formed inside the semiconductor element. In the center portion of FIG. 3, a p-pull-out region 19 is formed in the surface layer of the n-base layer so as to partially overlap the p-base region 4. This p extraction area 1
The emitter electrode 8 is in contact with the surface 9 and is for extracting holes in the n-base layer 3 at the boundary between the main IGBT part 13 and the sense IGBT part 14 during the OFF operation.

【００３２】センスエミッタストライプは一本で、長環
状のｎセンスエミッタ領域２５が断面では二本になって
いることがわかる。このため図１に点線で示したセンス
電流の流れる活性領域１７の面積は従来例に比べて、約
１／３になり、ゲート電圧印加時にｎセンスエミッタ領
域２５からセンスチャネル領域を通してｎベース層３に
注入される電子の量は大幅に減少する。また、センスエ
ミッタストライプが一本だけで孤立しているため、注入
された電子電流がｐｎｐトランジスタのベース電流とし
て働き難く、センスＩＧＢＴ部１４の伝導度変調が起き
にくくなつていると考えられる。It can be seen that the sense emitter stripe is one and the long n-type emitter emitter region 25 is two in cross section. Therefore, the area of the active region 17 through which the sense current flows shown by the dotted line in FIG. 1 is about 1/3 of that of the conventional example, and when the gate voltage is applied, the n sense emitter region 25 and the n base layer 3 pass through the sense channel region. The amount of electrons injected into is greatly reduced. Further, it is considered that since the sense emitter stripe is isolated by only one stripe, the injected electron current is hard to act as the base current of the pnp transistor, and conductivity modulation of the sense IGBT portion 14 is hard to occur.

【００３３】図２２にこの実施例１のＩＧＢＴのセンス
ＩＧＢＴ部１４の電流−電圧特性を示す。横軸は電圧
（Ｖ_CE）、縦軸は電流（Ｉ_C）である。比較のため、従
来の電流検知部内蔵型ＩＧＢＴの電流−電圧特性を点線
で示した。実施例１のセンスＩＧＢＴ部の曲線にはこの
電圧範囲では、従来の電流検知部内蔵型ＩＧＢＴのセン
スＩＧＢＴ部で見られた電流−電圧特性の負性抵抗領域
が発生していない。このため、センス電圧−コレクタ電
流特性に不連続領域が発生せず、センス電圧の温度依存
性が安定する。図２３に、常温、高温でのセンス電圧の
センス抵抗依存性を示す。横軸はセンス抵抗Ｒ_S、縦軸
はセンス電圧Ｖ_Sである。センス電圧Ｖ_Sは定格電流の
二倍の電流を流したときのセンス抵抗での電圧降下とし
た。比較のため、従来の電流検知部内蔵型ＩＧＢＴのそ
れも示した。２５℃、１２５℃の曲線ともに、折れ曲が
りが見られず、ほぼ線型で同じような傾向を示す。ま
た、２５℃、１２５℃の曲線が接近していて、温度依存
性が小さい。このことは、制限電流の設定が精密にでき
ることを意味している。〔実施例２〕図２に、本発明第二の実施例の電流検知部
内蔵型ＩＧＢＴのセンスＩＧＢＴ部１４近傍のゲート電
極中央における水平断面を示す。主ＩＧＢＴ部１３のス
トライプ状のエミッタ電極８、ゲート電極７に取り囲ま
れて、ｐ分離領域上の酸化膜１８があり、その中央部に
八角形のセンスゲート電極２７が見られる。センスエミ
ッタ電極２８は長いものが四本、短いものが二本で図１
４の従来例と同じであるが、隣り合ったセンスエミッタ
電極２８間のゲート電極２７の幅が狭くなっている点が
異なっている。従って、ストライプ状のセンスエミッタ
電極２８の下方には四本の長いセンスエミッタストライ
プと二本の短いセンスエミッタストライプがあることに
なる。FIG. 22 shows the current-voltage characteristics of the sense IGBT section 14 of the IGBT of the first embodiment. The horizontal axis represents voltage (V _CE ) and the vertical axis represents current (I _C ). For comparison, the current-voltage characteristics of the conventional IGBT with a built-in current detector are shown by the dotted line. In this voltage range, the curve of the sense IGBT portion of the first embodiment does not have the negative resistance region of the current-voltage characteristic found in the sense IGBT portion of the conventional IGBT with a built-in current detection portion. Therefore, a discontinuous region does not occur in the sense voltage-collector current characteristic, and the temperature dependence of the sense voltage becomes stable. FIG. 23 shows the sense resistance dependence of the sense voltage at normal temperature and high temperature. The horizontal axis represents the sense resistance R _S , and the vertical axis represents the sense voltage V _S. The sense voltage V _S is the voltage drop across the sense resistor when a current twice the rated current is applied. For comparison, a conventional IGBT with a built-in current detector is also shown. No bending is seen in both the 25 ° C. and 125 ° C. curves, and the curves are almost linear and show the same tendency. Further, the curves of 25 ° C. and 125 ° C. are close to each other, and the temperature dependence is small. This means that the limiting current can be set precisely. [Embodiment 2] FIG. 2 shows a horizontal cross section in the center of the gate electrode in the vicinity of the sense IGBT portion 14 of the current detection portion built-in type IGBT according to the second embodiment of the present invention. Surrounded by the stripe-shaped emitter electrode 8 and the gate electrode 7 of the main IGBT portion 13, there is an oxide film 18 on the p isolation region, and an octagonal sense gate electrode 27 can be seen in the center thereof. The sense emitter electrode 28 has four long ones and two short ones.
4 is the same as the conventional example, except that the width of the gate electrode 27 between the adjacent sense emitter electrodes 28 is narrowed. Therefore, there are four long sense emitter stripes and two short sense emitter stripes below the striped sense emitter electrode 28.

【００３４】図４に、図２のＢ−Ｂ’線に沿った部分断
面を示す。主ＩＧＢＴ部１３のゲート電極７の幅は、３
６μｍであるが、センスＩＧＢＴ部１４のセンスゲート
電極２７の幅は、１３μｍである。図２４にこの実施例
２のＩＧＢＴのセンスＩＧＢＴ部１４の電流−電圧特性
を示す。横軸は間電圧（Ｖ_CE）、縦軸は電流（Ｉ_C）で
ある。比較のため、従来例のセンスＩＧＢＴの電流−電
圧特性も示した。本実施例のセンスＩＧＢＴ部の特性に
はこの電圧範囲では、従来の電流検知部内蔵型ＩＧＢＴ
のセンスＩＧＢＴで見られた負性抵抗領域が発生してい
ない。本実施例のセンスＩＧＢＴ部の特性は、従来例の
センスＩＧＢＴの電流−電圧特性に対して、電流が流れ
難く、大きな抵抗性を示していることがわかる。この原
因は、センスエミッタ電極２８の間のセンスＩＧＢＴ部
１４のセンスゲート電極２７の幅を小さくすることによ
って、二つのｐセンスベース領域２４間のｎベース層３
の抵抗分が増す、いわゆる接合型ＦＥＴ効果によってセ
ンスＩＧＢＴ部のベース電流が減少し、ＩＧＢＴとして
の動作よりはＭＯＳＦＥＴに似た動作となるためであ
る。電流−電圧特性が線型性を示していることからもこ
のことが裏付けられる。FIG. 4 shows a partial cross section taken along the line BB 'in FIG. The width of the gate electrode 7 of the main IGBT portion 13 is 3
Although the width is 6 μm, the width of the sense gate electrode 27 of the sense IGBT portion 14 is 13 μm. FIG. 24 shows the current-voltage characteristics of the sense IGBT section 14 of the IGBT according to the second embodiment. The horizontal axis represents the inter-voltage (V _CE ) and the vertical axis represents the current (I _C ). For comparison, the current-voltage characteristics of the conventional sense IGBT are also shown. In this voltage range, the characteristics of the sense IGBT unit of the present embodiment are such that the conventional IGBT with a built-in current detection unit is used.
The negative resistance region seen in the sense IGBT of FIG. It can be seen that the characteristics of the sense IGBT portion of the present embodiment show a large resistance as compared with the current-voltage characteristics of the conventional sense IGBT, in which a current does not easily flow. The reason for this is that the width of the sense gate electrode 27 of the sense IGBT portion 14 between the sense emitter electrodes 28 is reduced, so that the n base layer 3 between the two p sense base regions 24 is reduced.
This is because the base current of the sense IGBT portion decreases due to the so-called junction-type FET effect in which the resistance component of is increased, and the operation becomes more like a MOSFET than the operation as an IGBT. This is supported by the fact that the current-voltage characteristics show linearity.

【００３５】図２３に、この実施例２の常温、高温での
センス電圧のセンス抵抗依存性も示した。２５℃、１２
５℃の曲線ともに、折れ曲がりが見られず、同じような
傾向を示す。また、２５℃、１２５℃の曲線が接近して
いて、温度依存性が小さい。このことは、制限電流の設
定が精密にできることを意味している。〔実施例３〕図５に、本発明第三の実施例の電流検知部
内蔵型ＩＧＢＴのセンスＩＧＢＴ部１４近傍の部分断面
を示す。FIG. 23 also shows the sense resistance dependence of the sense voltage at room temperature and high temperature in Example 2. 25 ° C, 12
No bending was observed on both curves at 5 ° C., and the same tendency was exhibited. Further, the curves of 25 ° C. and 125 ° C. are close to each other, and the temperature dependence is small. This means that the limiting current can be set precisely. [Embodiment 3] FIG. 5 shows a partial cross section in the vicinity of the sense IGBT portion 14 of the current detection portion built-in type IGBT according to the third embodiment of the present invention.

【００３６】この図は、図１５の従来例とほぼ同じに見
えるが、不純物濃度が異なっているのである。すなわ
ち、主ＩＧＢＴ部１３のｐベース領域４とセンスＩＧＢ
Ｔ部１４のｐセンスベース領域２４の表面濃度が異な
り、ｐセンスベース領域２４の表面濃度が約１．２倍高
くなっている。従って、これまでの実施例とは違って、
主ＩＧＢＴ部１３とセンスＩＧＢＴ部１４とを全く同時
には形成できない。製造方法としては、主ＩＧＢＴ部１
３のｐベース領域４とセンスＩＧＢＴ部１４のホウ素の
イオン注入量を変えて行う。This figure looks almost the same as the conventional example of FIG. 15, but the impurity concentration is different. That is, the p base region 4 of the main IGBT portion 13 and the sense IGBT
The surface concentration of the p-sense base region 24 of the T portion 14 is different, and the surface concentration of the p-sense base region 24 is about 1.2 times higher. Therefore, unlike the previous examples,
The main IGBT part 13 and the sense IGBT part 14 cannot be formed at the same time. As a manufacturing method, the main IGBT unit 1
The ion implantation amount of boron in the p base region 4 of 3 and the sense IGBT portion 14 is changed.

【００３７】このため、センスＩＧＢＴ部１４のしきい
値は主ＩＧＢＴ部１３のそれより高くなる。このように
センスＩＧＢＴ部１４のしきい値を増大させると、セン
スゲート電極２７にかかる実効的なゲート電圧が低下し
たと同じである。すなわち、センスＩＧＢＴ部の動作と
しては、ゲート電圧が低い分だけ、センスチャネル領域
３１にできる反転層が低減され、ｎセンスエミッタ領域
２５からｎベース層３に注入される電子電流が減少す
る。これにより、ｐコレクタ層１からの正孔の注入が抑
制されて、センスＩＧＢＴ部１４の動作が、ＭＯＳＦＥ
Ｔに似た動作になり、上記の例と同様にセンスＩＧＢＴ
部１４の電流−電圧特性は線型に近い特性を示すことに
なる。Therefore, the threshold value of the sense IGBT section 14 becomes higher than that of the main IGBT section 13. Increasing the threshold value of the sense IGBT portion 14 in this way is the same as decreasing the effective gate voltage applied to the sense gate electrode 27. That is, in the operation of the sense IGBT portion, the inversion layer formed in the sense channel region 31 is reduced and the electron current injected from the n sense emitter region 25 to the n base layer 3 is reduced by the amount corresponding to the lower gate voltage. As a result, the injection of holes from the p collector layer 1 is suppressed, and the operation of the sense IGBT section 14 is
The operation is similar to T, and the sense IGBT is the same as the above example.
The current-voltage characteristic of the portion 14 is close to a linear characteristic.

【００３８】その結果、センスＩＧＢＴ部１４の動作は
主ＩＧＢＴ部１３のそれからずれたものとなり、センス
電圧の温度依存性を小さくすることができる。〔実施例４〕図６に、本発明第四の実施例の電流検知部
内蔵型ＩＧＢＴのセンスＩＧＢＴ部１４近傍の部分断面
を示す。この実施例が従来例と異なっているのは、主Ｉ
ＧＢＴ部１３のチャネル領域１１のチャネル長よりもセ
ンスＩＧＢＴ部１４のセンスチャネル領域３１のそれが
長く形成されている点である。As a result, the operation of the sense IGBT section 14 deviates from that of the main IGBT section 13, and the temperature dependence of the sense voltage can be reduced. [Embodiment 4] FIG. 6 shows a partial cross section in the vicinity of the sense IGBT portion 14 of the current detection portion built-in type IGBT according to the fourth embodiment of the present invention. This embodiment is different from the conventional example in that the main I
This is that the sense channel region 31 of the sense IGBT unit 14 is formed longer than the channel length of the channel region 11 of the GBT unit 13.

【００３９】図２５にセンスＩＧＢＴ部１４のチャネル
長が長い場合と短い場合との電流−電圧特性の比較を示
す。チャネル長が長くなると、チャネル抵抗が増し、Ｍ
ＯＳＦＥＴの電圧降下が大きくなるが、電流−電圧特性
曲線に不連続領域が発生していない。逆にチャネル長が
短い従来例では（点線）、ＩＧＢＴとしての動作が大き
くなり、電流−電圧特性曲線に不連続領域が発生して、
センス電圧の温度依存性が悪化する。従って、センスチ
ャネル領域３１のチャネル長を長くすることにより、Ｍ
ＯＳＦＥＴに似た特性となり、その結果センス電圧の温
度依存性は向上する。FIG. 25 shows a comparison of current-voltage characteristics when the channel length of the sense IGBT section 14 is long and when it is short. As the channel length increases, the channel resistance increases and M
Although the voltage drop of the OSFET becomes large, the discontinuous region does not occur in the current-voltage characteristic curve. On the contrary, in the conventional example having a short channel length (dotted line), the operation as the IGBT becomes large, and a discontinuous region occurs in the current-voltage characteristic curve,
The temperature dependence of the sense voltage deteriorates. Therefore, by increasing the channel length of the sense channel region 31, M
The characteristics are similar to those of the OSFET, and as a result, the temperature dependence of the sense voltage is improved.

【００４０】一般に、ＩＧＢＴのチャネル長を長くする
と、ＩＧＢＴのオン電圧とスイッチング損失とのトレー
ドオフ特性が悪化する（図２６）。チャネル長が長くな
ると、チャネル抵抗が増し、ＭＯＳＦＥＴの電圧降下が
大きくなり、オン電圧が増大するためである。ＩＧＢＴ
のオン電圧全体にしめるＭＯＳＦＥＴの電圧降下の割合
が大きいので、オン電圧全体の低下を図るために、電子
線照射後のキャリアライフタイムの回復を大きくする
と、スイッチング損失の悪化を招くことになる。Generally, when the channel length of the IGBT is increased, the trade-off characteristic between the ON voltage of the IGBT and the switching loss is deteriorated (FIG. 26). This is because as the channel length increases, the channel resistance increases, the voltage drop of the MOSFET increases, and the on-voltage increases. IGBT
Since the ratio of the voltage drop of the MOSFET for the entire ON voltage is large, if the recovery of the carrier lifetime after electron beam irradiation is increased in order to reduce the overall ON voltage, the switching loss will be worsened.

【００４１】そこで、主ＩＧＢＴ部１３のチャネル長は
短いままとし、センスＩＧＢＴ部１４のチャネル領域３
１だけのチャネル長を長くすることが必要となる。〔実施例５〕図７に、本発明第五の実施例の電流検知部
内蔵型ＩＧＢＴのセンスＩＧＢＴ部１４近傍の部分断面
を示す。この実施例が従来例と異なっているのは、セン
スＩＧＢＴ部１４のゲート酸化膜２６上のセンスチャネ
ル領域３１上以外の部分に厚い酸化膜１８が形成されそ
の上にセンスゲート電極２７が形成されている点であ
る。主ＩＧＢＴ部１３のゲート酸化膜６は薄いままとす
る。Therefore, the channel length of the main IGBT part 13 is kept short and the channel region 3 of the sense IGBT part 14 is kept.
It is necessary to increase the channel length by only 1. [Embodiment 5] FIG. 7 shows a partial cross section in the vicinity of the sense IGBT portion 14 of the current detection portion built-in type IGBT according to a fifth embodiment of the present invention. This embodiment is different from the conventional example in that a thick oxide film 18 is formed on the gate oxide film 26 of the sense IGBT portion 14 other than on the sense channel region 31 and a sense gate electrode 27 is formed thereon. That is the point. The gate oxide film 6 of the main IGBT portion 13 is left thin.

【００４２】このように、テラス状のゲート酸化膜を形
成すると、センスＩＧＢＴ部１４のオン電圧が増大す
る。その理由は、センスチャネル領域３１上部以外のｎ
ベース層３上のセンスゲート酸化膜２６上に厚い酸化膜
１８を形成すると、ゲート電圧を印加した時、ｎベース
層３の表面層に生じる蓄積層２３のキャリア濃度が低
く、その伝導度が低下するためである。When the terrace-shaped gate oxide film is formed in this manner, the ON voltage of the sense IGBT portion 14 increases. The reason is that n other than the upper portion of the sense channel region 31
When the thick oxide film 18 is formed on the sense gate oxide film 26 on the base layer 3, when the gate voltage is applied, the carrier concentration of the storage layer 23 generated in the surface layer of the n base layer 3 is low and its conductivity is lowered. This is because

【００４３】センスＩＧＢＴ部１４のセンスゲート酸化
膜２６上に厚い酸化膜１８を形成することによって、セ
ンスＩＧＢＴ部１４はオンしにくくなり、主ＩＧＢＴ部
に比較してＭＯＳＦＥＴ類似の動作を示すことになる。
その結果、主ＩＧＢＴ部とセンスＩＧＢＴ部の動作特性
がずらされ、センス電圧の温度依存性を改善することが
できる。〔実施例６〕図８は、本発明第六の実施例の電流検知部
内蔵型ＩＧＢＴのセンスＩＧＢＴ部１４のエミッタスト
ライプ近傍の部分斜視図である。この実施例が従来例と
異なっているのは、ｐセンスベース領域２４の表面層に
ｎセンスエミッタ領域２５が断続する短冊状に形成され
ている点である。By forming the thick oxide film 18 on the sense gate oxide film 26 of the sense IGBT portion 14, it becomes difficult for the sense IGBT portion 14 to turn on, and the operation similar to the MOSFET is exhibited as compared with the main IGBT portion. Become.
As a result, the operating characteristics of the main IGBT part and the sense IGBT part are shifted, and the temperature dependence of the sense voltage can be improved. [Sixth Embodiment] FIG. 8 is a partial perspective view in the vicinity of an emitter stripe of a sense IGBT portion 14 of an IGBT with a built-in current detection portion according to a sixth embodiment of the present invention. This example differs from the conventional example in that an n-sense emitter region 25 is formed in a strip shape in the surface layer of the p-sense base region 24.

【００４４】このようにｎセンスエミッタ領域２５を部
分的に形成すれば、ゲートオン時にｎセンスエミッタ領
域２５からｎベース層３に注入される電子電流が減少す
ることになる。そして、下方のｐコレクタ層から注入さ
れる正孔が抑制され、ＭＯＳＦＥＴ類似の動作をするこ
とになる。その結果、センス電圧の温度依存性を改善す
ることができる。〔実施例７〕図９に、本発明第七の実施例の電流検知部
内蔵型ＩＧＢＴのセンスＩＧＢＴ部１４近傍の部分断面
を示す。この実施例が従来例と異なっているのは、セン
スエミッタ電極２８がｎセンスエミッタ領域２５にのみ
接触しており、ｐセンスウェル領域３０には別の分離電
極４１が接触している点である。ｎセンスエミッタ領域
２５とｐセンスウェル領域３０との境界の表面上は絶縁
膜で覆われている。By partially forming the n-sense emitter region 25 as described above, the electron current injected from the n-sense emitter region 25 into the n-base layer 3 at the time of gate-on is reduced. Then, the holes injected from the lower p collector layer are suppressed, and the MOSFET-like operation is performed. As a result, the temperature dependence of the sense voltage can be improved. [Embodiment 7] FIG. 9 shows a partial cross section in the vicinity of the sense IGBT portion 14 of the current detection portion built-in type IGBT according to a seventh embodiment of the present invention. This embodiment is different from the conventional example in that the sense emitter electrode 28 is in contact only with the n sense emitter region 25 and the p sense well region 30 is in contact with another separation electrode 41. . The surface of the boundary between the n sense emitter region 25 and the p sense well region 30 is covered with an insulating film.

【００４５】このような構造にすることによって、ＩＧ
ＢＴのディメンションをもちながら完全なＭＯＳＦＥＴ
としての動作をすることができる。以下、センスＩＧＢ
Ｔ部１４の動作を図９に沿って説明する。Ｃ端子にＳＥ
端子に対して正の電圧を印加した状態で、センスゲート
電極２７、にしきい値以上の電圧を印加することによつ
て、センスゲート電極２７の直下のｐセンスベース領域
２４の表面層に反転層が形成され、その反転層を通って
ｎセンスエミッタ領域２５から電子がｎベース層３、ｎ
⁺バッファ層２に注入される。（すなわち、ｎセンスエ
ミッタ領域２５、ｐセンスベース領域２４とｎベース層
３とからなるＭＯＳＦＥＴが導通する。）ｐコレクタ層
１とｎ⁺バッファ層２との間の接合は順バイアスされて
いるので、この接合から電子が注入される。この電子電
流は、ｐコレクタ層１、ｎ⁺バッファ層２とｎベース層
３、ｐセンスベース領域２４をそれぞれエミッタ、ベー
ス、コレクタとするｐｎｐトランジスタのベース電流と
なるので、このトランジスタが動作し、ｐコレクタ層１
から多量の正孔が注入されて伝導度変調を発生してＩＧ
ＢＴがオンする。このとき、ｐセンスベース領域２４上
には分離電極４１が設けられているので、正孔電流は分
離電極４１へ流入し、センスエミッタ電極２８には流れ
ない。従ってセンスエミッタ電極２８には電子電流しか
流れないことになる。このセンスエミッタ電極２８から
センス抵抗３２を介してエミッタ電極８に接続すること
によって、ＩＧＢＴの構造をもちながらＭＯＳＦＥＴと
しての動作をさせることができる。With such a structure, the IG
Complete MOSFET with dimensions of BT
Can operate as. Below, sense IGB
The operation of the T section 14 will be described with reference to FIG. SE on C terminal
By applying a voltage equal to or higher than the threshold value to the sense gate electrode 27 in the state where a positive voltage is applied to the terminal, the inversion layer is formed on the surface layer of the p-sense base region 24 immediately below the sense gate electrode 27. Through the inversion layer, electrons from the n sense emitter region 25 are transferred to the n base layer 3, n.
⁺ Injected into the buffer layer 2. (That is, the MOSFET composed of the n-sense emitter region 25, the p-sense base region 24 and the n-base layer 3 becomes conductive.) Since the junction between the p-collector layer 1 and the n ⁺ buffer layer 2 is forward biased. , Electrons are injected from this junction. This electron current becomes a base current of a pnp transistor having the p collector layer 1, the n ⁺ buffer layer 2 and the n base layer 3, and the p sense base region 24 as an emitter, a base, and a collector, respectively. p collector layer 1
A large amount of holes are injected from the
BT turns on. At this time, since the separation electrode 41 is provided on the p-sense base region 24, the hole current flows into the separation electrode 41 and does not flow into the sense emitter electrode 28. Therefore, only the electron current flows through the sense emitter electrode 28. By connecting the sense emitter electrode 28 to the emitter electrode 8 via the sense resistor 32, it is possible to operate as a MOSFET while having an IGBT structure.

【００４６】このように、センスＩＧＢＴ部１４をＭＯ
ＳＦＥＴとして動作させるために、その電流−電圧特性
はＭＯＳＦＥＴとしての特性を示すことになり、センス
電圧の温度依存性を改善することができる。〔実施例８〕図１０に、本発明第八の実施例の電流検知
部内蔵型ＩＧＢＴのセンスＩＧＢＴ部１４近傍の部分断
面を示す。この実施例が従来例と異なっているのは、主
ＩＧＢＴ部１３のエミッタ電極８とセンスＩＧＢＴ部１
４のセンスエミッタ電極２８との間にセンス抵抗３２と
直列にダイオード３３が挿入されている点である。In this way, the sense IGBT unit 14 is
In order to operate as an SFET, its current-voltage characteristics show characteristics of a MOSFET, and the temperature dependence of the sense voltage can be improved. [Embodiment 8] FIG. 10 shows a partial cross section in the vicinity of the sense IGBT portion 14 of the current detection portion built-in type IGBT according to an eighth embodiment of the present invention. This embodiment differs from the conventional example in that the emitter electrode 8 of the main IGBT portion 13 and the sense IGBT portion 1 are
The point is that the diode 33 is inserted in series with the sense resistor 32 between the sense emitter electrode 28 of FIG.

【００４７】図１２にこの実施例８の等価回路を示す。
このような構造にすることにより、センスＩＧＢＴ部１
４のセンスエミッタ電極２８にかかる電圧は、主ＩＧＢ
Ｔ部１３のエミッタ電極８の電圧より、ダイオード３３
の順電圧分だけ低下することになる。その結果センスＩ
ＧＢＴ部１４の電流−電圧特性曲線の負性抵抗領域には
かからなくなる。そして、センス電圧の温度依存性を低
減することが可能となる。〔実施例９〕図１１に、本発明第九の実施例の電流検知
部内蔵型ＩＧＢＴのセンスＩＧＢＴ部１４近傍の部分断
面を示す。この例は上記実施例８の変形例であり、ダイ
オード３３が、ＩＧＢＴチップ上に形成されているもの
である。すなわち、センスＩＧＢＴ部１４のｐ分離領域
１６を覆う酸化膜１８上に多結晶シリコンのｐアノード
領域３４とｎカソード領域３５からなるダイオード３３
が形成されている。ｐアノード領域３４には、センスエ
ミッタ電極２８が接触し、ｎカソード領域３５に接触す
るカソード電極は、センス抵抗３２を介してエミッタ電
極８に接続される。FIG. 12 shows an equivalent circuit of the eighth embodiment.
With such a structure, the sense IGBT unit 1
The voltage applied to the sense emitter electrode 28 of No. 4 is
From the voltage of the emitter electrode 8 of the T portion 13, the diode 33
Will be reduced by the forward voltage. As a result, sense I
It does not apply to the negative resistance region of the current-voltage characteristic curve of the GBT unit 14. Then, the temperature dependence of the sense voltage can be reduced. [Embodiment 9] FIG. 11 shows a partial cross section in the vicinity of the sense IGBT portion 14 of a current detection portion built-in type IGBT according to a ninth embodiment of the present invention. This example is a modification of the above-described eighth embodiment, and the diode 33 is formed on the IGBT chip. That is, the diode 33 including the p anode region 34 and the n cathode region 35 of polycrystalline silicon is formed on the oxide film 18 covering the p isolation region 16 of the sense IGBT portion 14.
Are formed. A sense emitter electrode 28 is in contact with the p anode region 34, and a cathode electrode in contact with the n cathode region 35 is connected to the emitter electrode 8 via the sense resistor 32.

【００４８】この実施例９の電流検知部内蔵型ＩＧＢＴ
の動作は実施例８と同様であり、センス電圧の温度依存
性を低減することが可能となる。IGBT with a built-in current detector of the ninth embodiment
The operation of is similar to that of the eighth embodiment, and the temperature dependence of the sense voltage can be reduced.

【００４９】[0049]

【発明の効果】以上説明したように本発明によれば、主
ＩＧＢＴ部とセンスＩＧＢＴ部とを有し、エミッタ電極
とセンスエミッタ電極との間に接続された抵抗での電圧
降下を利用する電流検知部内蔵型ＩＧＢＴにおいて、第
二導電型センスベース領域のストライプを一本にした
り、センスエミッタ電極間のセンスゲート電極の幅を狭
くしたり、センスゲートのしきい値を主ＩＧＢＴ部のゲ
ートのしきい値より高くするなどの手段により、保護の
ため検知すべき電流水準における主ＩＧＢＴのオン電圧
以下の範囲で、センスＩＧＢＴの電流−電圧特性をほぼ
線型にすることによって、センス電圧の不連続点をなく
し、センス電圧の温度依存性を改善することができる。
その結果、電流の検知精度が大幅に高められ、確実に半
導体素子および回路が保護されるようになる。As described above, according to the present invention, a current having a main IGBT portion and a sense IGBT portion and utilizing a voltage drop at a resistor connected between an emitter electrode and a sense emitter electrode is used. In the detector built-in type IGBT, the stripes of the second conductivity type sense base region are made one, the width of the sense gate electrode between the sense emitter electrodes is narrowed, and the threshold of the sense gate is set to the gate of the main IGBT part. The sense voltage is discontinuous by making the current-voltage characteristic of the sense IGBT almost linear within a range below the on-voltage of the main IGBT at the current level to be detected for protection by means such as making it higher than the threshold value. The point can be eliminated and the temperature dependence of the sense voltage can be improved.
As a result, the current detection accuracy is significantly improved, and the semiconductor element and the circuit are surely protected.

【００５０】また、エミッタ電極とセンスエミッタ電極
との間にダイオードを挿入することにより、同様の効果
が得られることを示した。It was also shown that the same effect can be obtained by inserting a diode between the emitter electrode and the sense emitter electrode.

[Brief description of drawings]

【図１】本発明第一の実施例の電流検知部内蔵型ＩＧＢ
Ｔのゲート電極中央における水平断面図FIG. 1 is a first embodiment of the present invention, a current detection unit built-in IGBT.
Horizontal sectional view of the gate electrode center of T

【図２】本発明第二の実施例の電流検知部内蔵型ＩＧＢ
Ｔのゲート電極中央における水平断面図FIG. 2 is a second embodiment of the present invention built-in current detector IGB.
Horizontal sectional view of the gate electrode center of T

【図３】図１の実施例のＡ−Ａ’線に沿った部分断面図FIG. 3 is a partial cross-sectional view taken along the line A-A ′ of the embodiment of FIG.

【図４】図３の実施例のＢ−Ｂ’線に沿った部分断面図FIG. 4 is a partial cross-sectional view taken along the line B-B ′ of the embodiment of FIG.

【図５】本発明第三の実施例の電流検知部内蔵型ＩＧＢ
Ｔの部分断面図FIG. 5 is an IGBT with a built-in current detector according to a third embodiment of the present invention.
Partial sectional view of T

【図６】本発明第四の実施例の電流検知部内蔵型ＩＧＢ
Ｔの部分断面図FIG. 6 is an IGBT with a built-in current detector according to a fourth embodiment of the present invention.
Partial sectional view of T

【図７】本発明第五の実施例の電流検知部内蔵型ＩＧＢ
Ｔの部分断面図FIG. 7 is an IGBT with a built-in current detector according to a fifth embodiment of the present invention.
Partial sectional view of T

【図８】本発明第六の実施例の電流検知部内蔵型ＩＧＢ
Ｔの部分断面図FIG. 8 is an IGBT with a built-in current detection unit according to a sixth embodiment of the present invention.
Partial sectional view of T

【図９】本発明第七の実施例の電流検知部内蔵型ＩＧＢ
Ｔの部分斜視図FIG. 9 is an IGBT with a built-in current detector according to a seventh embodiment of the present invention.
Partial perspective view of T

【図１０】本発明第八の実施例の電流検知部内蔵型ＩＧ
ＢＴの部分断面図FIG. 10 is a current detection unit built-in IG according to an eighth embodiment of the present invention.
Partial sectional view of BT

【図１１】本発明第九の実施例の電流検知部内蔵型ＩＧ
ＢＴの部分断面図FIG. 11 is an IG with a built-in current detector according to a ninth embodiment of the present invention.
Partial sectional view of BT

【図１２】本発明第八の実施例の等価回路図FIG. 12 is an equivalent circuit diagram of an eighth embodiment of the present invention.

【図１３】電流検知部内蔵型ＩＧＢＴを使用した回路の
図FIG. 13 is a diagram of a circuit using an IGBT with a built-in current detection unit.

【図１４】従来の電流検知部内蔵型ＩＧＢＴのゲート電
極中央における水平断面図FIG. 14 is a horizontal cross-sectional view in the center of the gate electrode of a conventional IGBT with a built-in current detector

【図１５】図１４の従来例のＣ−Ｃ’線に沿った部分断
面図FIG. 15 is a partial cross-sectional view taken along the line CC ′ of the conventional example of FIG.

【図１６】過電流時のタイミングチャートFIG. 16 is a timing chart at the time of overcurrent

【図１７】負荷短絡時のタイミングチャートFIG. 17 is a timing chart when a load is short-circuited.

【図１８】ＩＰＭの保護回路の図FIG. 18 is a diagram of a protection circuit of the IPM.

【図１９】（ａ）、（ｂ）は負荷短絡時の電流、電圧波
形図19 (a) and 19 (b) are current and voltage waveform diagrams when a load is short-circuited.

【図２０】従来の電流検知部内蔵型ＩＧＢＴのセンス電
圧の温度依存性を示す図FIG. 20 is a diagram showing the temperature dependence of the sense voltage of a conventional IGBT with a built-in current detector.

【図２１】従来の電流検知部内蔵型ＩＧＢＴのセンスＩ
ＧＢＴ部の電流−電圧特性図FIG. 21 is a sense I of a conventional IGBT with a built-in current detector.
Current-voltage characteristic diagram of GBT

【図２２】本発明第一の実施例の電流検知部内蔵型ＩＧ
ＢＴのセンスＩＧＢＴ部の電流−電圧特性図FIG. 22 is a current detection unit built-in IG according to the first embodiment of the present invention.
Current-voltage characteristic diagram of sense IGBT part of BT

【図２３】本発明第一、第二の実施例の電流検知部内蔵
型ＩＧＢＴのセンス電圧の温度依存性を示す図FIG. 23 is a diagram showing the temperature dependence of the sense voltage of the current detection section built-in type IGBTs according to the first and second embodiments of the present invention.

【図２４】本発明第二の実施例の電流検知部内蔵型ＩＧ
ＢＴのセンスＩＧＢＴ部の電流−電圧特性図FIG. 24 is a current detection section built-in IG according to a second embodiment of the present invention.
Current-voltage characteristic diagram of sense IGBT part of BT

【図２５】本発明第四の実施例の電流検知部内蔵型ＩＧ
ＢＴのセンスＩＧＢＴ部の電流−電圧特性の温度依存性
を示す図FIG. 25 is a current detection section built-in IG according to a fourth embodiment of the present invention.
The figure which shows the temperature dependence of the current-voltage characteristic of the sense IGBT part of BT.

【図２６】本発明第四の実施例の電流検知部内蔵型ＩＧ
ＢＴのオン電圧−スイッチング損失のトレードオフ特性
図FIG. 26 is a current detection section built-in IG according to a fourth embodiment of the present invention.
BT on-voltage-switching loss trade-off characteristic diagram

【図２７】主ＩＧＢＴ部の電流−電圧特性図FIG. 27 is a current-voltage characteristic diagram of the main IGBT section.

[Explanation of symbols]

１ｐコレクタ層２ｎ⁺バッファ層３ｎベース層４ｐベース領域５ｎエミッタ領域６ゲート酸化膜７ゲート電極８エミッタ電極９コレクタ電極１０ｐウェル領域１１チャネル領域１３主ＩＧＢＴ部１４センスＩＧＢＴ部１５絶縁膜１６ｐ分離領域１７活性領域１８酸化膜１９ｐ引き抜き領域２０保護回路２１負荷２２電源２３蓄積層２４ｐセンスベース領域２５ｎセンスエミッタ領域２６センスゲート酸化膜２７センスゲート電極２８センスエミッタ電極３０ｐセンスウェル領域３１センスチャネル領域３２、３２ａ、３２ｂセンス抵抗３３センスダイオード３４ｐセンスアノード領域３５ｎセンスカソード領域４１分離電極1 p collector layer 2 n ⁺ buffer layer 3 n base layer 4 p base region 5 n emitter region 6 gate oxide film 7 gate electrode 8 emitter electrode 9 collector electrode 10 p well region 11 channel region 13 main IGBT part 14 sense IGBT part 15 Insulating film 16 p Isolation region 17 Active region 18 Oxide film 19 p Extraction region 20 Protection circuit 21 Load 22 Power supply 23 Storage layer 24 p Sense base region 25 n Sense emitter region 26 Sense gate oxide film 27 Sense gate electrode 28 Sense emitter electrode 30 p sense well region 31 sense channel region 32, 32a, 32b sense resistor 33 sense diode 34 p sense anode region 35 n sense cathode region 41 isolation electrode

───────────────────────────────────────────────────── フロントページの続き (72)発明者工藤基神奈川県川崎市川崎区田辺新田１番１号富士電機株式会社内 ──────────────────────────────────────────────────続き Continuing on the front page (72) Inventor Motoki Kudo 1-1-1 Tanabe Shinda, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fuji Electric Co., Ltd.

Claims

[Claims]

1. A first conductivity type semiconductor layer, a second conductivity type base region selectively formed on a surface layer on one side of the first conductivity type semiconductor layer, and a second conductivity type base region. On the surface of the channel region, which is the portion between the first conductivity type emitter region selectively formed in the surface layer and the first conductivity type semiconductor layer of the second conductivity type base region and the first conductivity type emitter region. A gate electrode formed via a gate insulating film, an emitter electrode commonly contacting the surfaces of the second conductivity type base region and the first conductivity type emitter region other than the channel region, and the surface of the first conductivity type semiconductor layer. A second conductivity type collector region formed in another portion of the layer, a collector electrode provided in contact with the surface of the second conductivity type collector region, and a surface of one side of the first conductivity type semiconductor layer. Second conductivity type base region in another part of layer A main insulated gate bipolar transistor (hereinafter abbreviated as main IGBT) portion, which is partially overlapped and has a second conductivity type extraction region in contact with the emitter electrode on the surface, and a first conductivity type semiconductor layer or less Of the second conductivity type sense base region formed in a region of the surface layer of the first conductivity type semiconductor layer adjacent to the second conductivity type extraction region, and the second conductivity type sense base. A first conductivity type sense emitter region selectively formed in the surface layer of the region, and a sense that is a part of the second conductivity type sense base region sandwiched between the first conductivity type semiconductor layer and the first conductivity type sense emitter region. A sense gate electrode formed on the surface of the channel region via a sense gate insulating film, a second conductivity type sense base region other than the sense channel region, and a first conductivity type sense emitter. A sense insulated gate bipolar transistor (hereinafter abbreviated as sense IGBT) portion for current detection, which includes a sense emitter electrode in common contact on the surface of the region, and is connected between the emitter electrode and the sense emitter electrode. In an insulated gate bipolar transistor with a built-in current detection unit (hereinafter abbreviated as IGBT with a built-in current detection unit) that utilizes the voltage drop across a resistor, in the range below the on-voltage of the main IGBT at the current level to be detected for protection, IG with a built-in current detector, wherein the current-voltage characteristic of the sense IGBT unit is linear
BT.

2. The current detection part built-in IGBT according to claim 1, wherein the second conductivity type sense base region has a single stripe shape.

3. The current detection unit built-in IGBT according to claim 1, wherein the width of the sense gate electrode between the sense emitter electrodes of the sense IGBT unit is narrower than the width of the gate electrode of the main IGBT unit.

4. The current detection unit built-in IGBT according to claim 1, wherein the threshold value of the gate of the sense IGBT section is higher than the threshold value of the gate of the main IGBT section.

5. The current sensing part built-in type according to claim 4, wherein the surface impurity concentration of the second conductivity type sense base region of the sense IGBT part is higher than that of the second conductivity type base region of the main IGBT part. IGBT.

6. The current sensing part built-in IGBT according to claim 1, wherein a channel length of the sense channel region of the sense IGBT part is longer than that of the channel region of the main IGBT part.

7. The current sensing part built-in IGBT according to claim 1, wherein a thick oxide film is partially formed on the sense gate oxide film.

8. The current detection unit built-in IGBT according to claim 1, wherein the first conductivity type sense emitter region has an intermittent strip-shaped portion.

9. A first conductivity type semiconductor layer, a second conductivity type base region selectively formed in a surface layer on one side of the first conductivity type semiconductor layer, and a second conductivity type base region. On the surface of the channel region, which is the portion between the first conductivity type emitter region selectively formed in the surface layer and the first conductivity type semiconductor layer of the second conductivity type base region and the first conductivity type emitter region. A gate electrode formed via a gate insulating film, an emitter electrode commonly contacting the surfaces of the second conductivity type base region and the first conductivity type emitter region other than the channel region, and the surface of the first conductivity type semiconductor layer. A second conductivity type collector region formed in another portion of the layer, a collector electrode provided in contact with the surface of the second conductivity type collector region, and a surface layer on one side of the first conductivity type semiconductor layer A second conductivity type base region on another part of the A main IGBT part formed of a second conductivity type extraction region in contact with the emitter electrode on the surface and a part below the first conductivity type semiconductor layer are shared with the main IGBT part. A second conductivity type sense base region formed in a region adjacent to the second conductivity type extraction region of the surface layer of the conductivity type semiconductor layer, and a first selectively formed on the surface layer of the second conductivity type sense base region. The sense gate insulating film is formed on the surface of the sense channel region, which is a portion sandwiched between the conductivity type sense emitter region, the first conductivity type semiconductor layer of the second conductivity type sense base region, and the first conductivity type sense emitter region. The formed sense gate electrode,
A sense IG for sensing current, comprising a sense emitter electrode in contact with the surface of the first conductivity type sense emitter region
In an IGBT with a built-in current detection part, which has a BT part and utilizes a voltage drop at a resistor connected between an emitter electrode and a sense emitter electrode, a separation electrode is provided on the surface of a second conductivity type sense base region. An IGBT with a built-in current detection unit, which is provided and is connected to an emitter electrode of a main IGBT unit.

10. A first conductivity type semiconductor layer, a second conductivity type base region selectively formed in a surface layer on one side of the first conductivity type semiconductor layer, and a second conductivity type base region. On the surface of the channel region, which is the portion between the first conductivity type emitter region selectively formed in the surface layer and the first conductivity type semiconductor layer of the second conductivity type base region and the first conductivity type emitter region. A gate electrode formed via a gate insulating film, an emitter electrode commonly contacting the surfaces of the second conductivity type base region and the first conductivity type emitter region other than the channel region, and the surface of the first conductivity type semiconductor layer. A second conductivity type collector region formed in another portion of the layer, a collector electrode provided in contact with the surface of the second conductivity type collector region, and a surface layer on one side of the first conductivity type semiconductor layer A second conductivity type base region in another part of A main IGBT part formed by overlapping second portions and having a second conductivity type extraction region in contact with the emitter electrode on the surface, and a part below the first conductivity type semiconductor layer in common with the main IGBT part, A second conductivity type sense base region formed in a region of the surface layer of the one conductivity type semiconductor layer adjacent to the second conductivity type extraction region, and a second conductivity type sense base region selectively formed on the surface layer of the second conductivity type sense base region. The sense gate insulating film is formed on the surface of the sense channel region, which is a portion sandwiched between the first conductivity type semiconductor layer of the first conductivity type sense emitter region and the first conductivity type sense emitter region of the second conductivity type sense base region. A sense gate electrode formed by
A sense IGBT part for current detection, which comprises a sense emitter electrode in common contact on the surfaces of a second conductivity type sense base region other than the sense channel region and a first conductivity type sense emitter region, and an emitter electrode. A current detection unit built-in type IGBT utilizing a voltage drop at a resistor connected between the sense emitter electrode and the sense emitter electrode, characterized in that a diode is connected between the emitter electrode and the sense emitter electrode. IGBT.

11. A first conductivity type semiconductor layer, a second conductivity type base region selectively formed in a surface layer on one side of the first conductivity type semiconductor layer, and a second conductivity type base region. On the surface of the channel region, which is the portion between the first conductivity type emitter region selectively formed in the surface layer and the first conductivity type semiconductor layer of the second conductivity type base region and the first conductivity type emitter region. A gate electrode formed via a gate insulating film, an emitter electrode commonly contacting the surfaces of the second conductivity type base region and the first conductivity type emitter region other than the channel region, and the surface of the first conductivity type semiconductor layer. A second conductivity type collector region formed in another portion of the layer, a collector electrode provided in contact with the surface of the second conductivity type collector region, and a surface of one side of the first conductivity type semiconductor layer. A second conductivity type base region is provided on another part of the layer. And a main IGBT part formed of a second conductivity type extraction region in contact with the emitter electrode on the surface, and a part below the first conductivity type semiconductor layer in common with the main IGBT part. A second conductivity type sense base region formed in a region of the surface layer of the first conductivity type semiconductor layer adjacent to the second conductivity type extraction region, and selectively formed on the surface layer of the second conductivity type sense base region. And a sense gate insulating film on the surface of the sense channel region, which is a portion sandwiched between the first conductivity type sense emitter region, the first conductivity type semiconductor layer of the second conductivity type sense base region, and the first conductivity type sense emitter region. And a sense emitter electrode formed on the surfaces of the second conductivity type sense base region and the first conductivity type sense emitter region other than the sense channel region in common contact with each other. And a sense IGBT part for detecting a current, and a diode is formed on a chip in a current detection part built-in IGBT that utilizes a voltage drop at a resistor connected between an emitter electrode and a sense emitter electrode. And a second conductivity type anode region of the diode is connected to the sense emitter electrode.