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JPH06140632A - Semiconductor device - Google Patents

Semiconductor device

Info

Publication number
JPH06140632A
JPH06140632A JP28804892A JP28804892A JPH06140632A JP H06140632 A JPH06140632 A JP H06140632A JP 28804892 A JP28804892 A JP 28804892A JP 28804892 A JP28804892 A JP 28804892A JP H06140632 A JPH06140632 A JP H06140632A
Authority
JP
Japan
Prior art keywords
conductivity type
layer
type
epitaxial layer
element isolation
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.)
Granted
Application number
JP28804892A
Other languages
Japanese (ja)
Other versions
JP2871352B2 (en
Inventor
Yukimasa Koishikawa
幸正 小石川
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
Original Assignee
NEC Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by NEC Corp filed Critical NEC Corp
Priority to JP28804892A priority Critical patent/JP2871352B2/en
Publication of JPH06140632A publication Critical patent/JPH06140632A/en
Application granted granted Critical
Publication of JP2871352B2 publication Critical patent/JP2871352B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Abstract

PURPOSE:To prevent the destruction of a vertical type MOSFET due to a counter-electromotive force occurring when an inductive load is driven by providing the vertical type MOSFET of a power IC having a vertical type MOSFET with a built-in diode having a low reverse breakdown voltage. CONSTITUTION:In a vertical type MOSFET of a power IC in which a p-type epitaxial layer 2 and an n-type epitaxial layer 4 are disposed and the vertical MOSFET and a control circuit are isolated from each other by an element isolation layer 5, a diode having a low reverse breakdown voltage is created by forming an n<+>-type diffusion layer 6 while it is in contact with the element isolation layer 5 within the n-type epitaxial layer 4.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は半導体装置に関し、特に
縦型MOSFETを有するパワーICに関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a power IC having a vertical MOSFET.

【0002】[0002]

【従来の技術】パワーICでは、縦型MOSFETとコ
ントロール回路が1チップ上に形成されており、その分
離の為に、エピタキシャル層を2層に積層している。
2. Description of the Related Art In a power IC, a vertical MOSFET and a control circuit are formed on one chip, and two epitaxial layers are stacked to separate them.

【0003】図3は従来の半導体装置の一例を示す断面
図である。
FIG. 3 is a sectional view showing an example of a conventional semiconductor device.

【0004】図3に示すように、N型シリコン基板1上
に設けたP型エピタキシャル層2と、その一部にN型不
純物を拡散して設けたN型の埋込拡散層3と、埋込拡散
層3を含む表面に設けたN型エピタキシャル層4と、N
型エピタキシャル層4に設けたP型の素子分離層5を有
しており、素子分離層5で分離されたN型エピタキシャ
ル層4内にP型ウェル8及びP型ベース領域9とを設
け、ベース領域9内にゲート電極11に整合してN型ソ
ース領域10を設けて縦型MOSFETを形成する。ま
た、絶縁膜7に設けたコンタクト孔を介してN型ソース
領域10及びP型ウェルを接続するソース電極12と素
子分離層5と接続する引出電極13が設けられる。
As shown in FIG. 3, a P-type epitaxial layer 2 provided on an N-type silicon substrate 1, an N-type buried diffusion layer 3 provided by diffusing N-type impurities in a part thereof, and a buried type An N-type epitaxial layer 4 provided on the surface including the diffusion layer 3;
A P type well 8 and a P type base region 9 are provided in the N type epitaxial layer 4 separated by the element separating layer 5. An N-type source region 10 is provided in the region 9 in alignment with the gate electrode 11 to form a vertical MOSFET. In addition, a source electrode 12 that connects the N-type source region 10 and the P-type well and a lead electrode 13 that connects the element isolation layer 5 are provided through a contact hole provided in the insulating film 7.

【0005】ここで、素子分離層5とN型エピタキシャ
ル層4を逆バイアスすることで、縦型MOSFETとコ
ントロール回路は電気的に分離される。
By reverse biasing the element isolation layer 5 and the N-type epitaxial layer 4, the vertical MOSFET and the control circuit are electrically isolated.

【0006】次に、縦型MOSFETの動作について説
明する。通常の動作において、ドレイン電極14にはプ
ラス電位を印加し、ソース電極12を接地する。ここ
で、ゲート電極11にプラス電位を与えると、P型ベー
ス領域9の表面にN型反転層が形成され、電流がドレイ
ン電極14からN型シリコン基板1,N型埋込拡散層
3,N型エピタキシャル層4,P型ベース領域9の表面
N型反転層,N型ソース領域10を順に通り、ソース電
極12に流れる。
Next, the operation of the vertical MOSFET will be described. In normal operation, a positive potential is applied to the drain electrode 14 and the source electrode 12 is grounded. Here, when a positive potential is applied to the gate electrode 11, an N-type inversion layer is formed on the surface of the P-type base region 9, and a current flows from the drain electrode 14 to the N-type silicon substrate 1, the N-type buried diffusion layer 3, and N. It flows through the type epitaxial layer 4, the surface N type inversion layer of the P type base region 9, and the N type source region 10 in this order to the source electrode 12.

【0007】縦型FETの使用例として、コイルなどの
誘導性負荷を駆動する場合がある。この動作を縦型MO
SFETの等価回路図4を用いて説明する。トランジス
タQ1 がオンしている場合、電流I1 が流れる。次にゲ
ート11をローレベルにして、トランジスタQ1 をオフ
した場合、I1 はただちに流れなくなるが、誘導性負荷
の逆起電力によって、ダイオードD1 ,D2 をブレーク
ダウンさせ、電流I2,I3 ,I4 が流れる。
As an example of using the vertical FET, there is a case of driving an inductive load such as a coil. This operation is vertical MO
An equivalent circuit of the SFET will be described with reference to FIG. When the transistor Q 1 is on, the current I 1 flows. Next, when the gate 11 is turned to the low level and the transistor Q 1 is turned off, I 1 stops flowing immediately, but the back electromotive force of the inductive load causes the diodes D 1 and D 2 to break down and the current I 2 , I 3 and I 4 flow.

【0008】ここで、I3 は寄生NPNトランジスタQ
2 のベースに流れるため、トランジスタをオンさせ、素
子を破壊させることがある。これをふせぐために一般に
ベース抵抗R2 を小さくする事がおこなわれている。ま
た、ダイオードD2 は、コントロール回路と縦型MOS
FETを完全に分離するために、ダイオード17よりも
高い逆耐圧をもつ様に通常設計される。このため、逆起
電力によって流れる電流は主にI2 ,I3 となる。
Where I 3 is a parasitic NPN transistor Q
Since it flows to the base of No. 2 , it may turn on the transistor and destroy the device. In order to prevent this, the base resistance R 2 is generally reduced. Further, the diode D 2 is a control circuit and a vertical MOS.
It is usually designed to have a higher reverse breakdown voltage than the diode 17 in order to completely isolate the FET. Therefore, the currents flowing by the counter electromotive force are mainly I 2 and I 3 .

【0009】[0009]

【発明が解決しようとする課題】この従来の半導体装置
では、縦型MOSFETを用いて誘導性負荷を駆動する
場合、逆起電力によって、トランジスタが破壊するとい
う問題があった。
This conventional semiconductor device has a problem in that when a vertical MOSFET is used to drive an inductive load, the transistor is destroyed by the back electromotive force.

【0010】[0010]

【課題を解決するための手段】本発明の第1の半導体装
置は、一導電型半導体基板の一主面に設けた逆導電型エ
ピタキシャル層と、前記逆導電型エピタキシャル層に設
けて前記半導体基板に達する一導電型埋込拡散層と、前
記一導電型拡散層を含む表面に設けた一導電型エピタキ
シャル層と、前記一導電型エピタキシャル層に設けて前
記逆導電型エピタキシャル層に達する逆導電型の素子分
離層と、前記素子分離層で分離された前記一導電型エピ
タキシャル層内に設けた逆導電型のベース領域と、前記
ベース領域内に設けた一導電型のソース領域とを有する
半導体装置において、分離された前記一導電型エピタキ
シャル層内の前記素子分離層に接して設けた一導電型の
高濃度拡散層を有する。
According to a first semiconductor device of the present invention, a reverse conductivity type epitaxial layer is provided on one main surface of a one conductivity type semiconductor substrate, and the semiconductor substrate is provided on the reverse conductivity type epitaxial layer. To the first conductivity type buried diffusion layer, a single conductivity type epitaxial layer provided on the surface including the first conductivity type diffusion layer, and a reverse conductivity type reaching the reverse conductivity type epitaxial layer provided in the first conductivity type epitaxial layer. A semiconductor device having a device isolation layer, a base region of opposite conductivity type provided in the epitaxial layer of one conductivity type separated by the device isolation layer, and a source region of one conductivity type provided in the base region. In the separated one-conductivity-type epitaxial layer, the one-conductivity-type high-concentration diffusion layer provided in contact with the element isolation layer.

【0011】本発明の第2の半導体装置は、一導電型半
導体基板の一主面に設けた逆導電型エピタキシャル層
と、前記逆導電型エピタキシャル層に設けて前記半導体
基板に達する一導電型埋込拡散層と、前記一導電型拡散
層を含む表面に設けた一導電型エピタキシャル層と、前
記一導電型エピタキシャル層に設けて前記逆導電型エピ
タキシャル層に達する逆導電型の素子分離層と、前記素
子分離層で分離された前記一導電型エピタキシャル層内
に設けた逆導電型のベース領域と、前記ベース領域内に
設けた一導電型のソース領域とを有する半導体装置にお
いて、前記逆導電型エピタキシャル層内の前記一導電型
埋込拡散層及び前記素子分離層に接して設けた一導電型
の高濃度埋込拡散層を有する。
A second semiconductor device of the present invention comprises a reverse conductivity type epitaxial layer provided on one main surface of a conductivity type semiconductor substrate, and a conductivity type buried layer reaching the semiconductor substrate by being provided on the reverse conductivity type epitaxial layer. Embedded diffusion layer, one conductivity type epitaxial layer provided on the surface including the one conductivity type diffusion layer, a reverse conductivity type element isolation layer provided in the one conductivity type epitaxial layer to reach the reverse conductivity type epitaxial layer, A semiconductor device having a base region of opposite conductivity type provided in the epitaxial layer of one conductivity type separated by the element isolation layer, and a source region of one conductivity type provided in the base region, wherein the opposite conductivity type is provided. The semiconductor device includes a one-conductivity-type buried diffusion layer provided in contact with the one-conductivity-type buried diffusion layer and the element isolation layer in an epitaxial layer.

【0012】[0012]

【実施例】次に、本発明について図面を参照して説明す
る。
DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

【0013】図1は本発明の第1の実施例を示す断面図
である。
FIG. 1 is a sectional view showing a first embodiment of the present invention.

【0014】図1に示すように、N型シリコン基板1の
上に設けたP型エピタキシャル層2に選択的にN型不純
物を拡散して設け且つN型シリコン基板1と接続するN
型埋込拡散層3と、N型埋込層3を含む表面に設けたN
型エピタキシャル層4と、N型エピタキシャル層4に設
けてP型エピタキシャル層2に達するP型の素子分離層
5と、素子分離層5により区画された素子形成領域内に
設けたP型ベース領域9及びP型ウェル8と、P型ベー
ス領域9上に絶縁膜7を介して設けたゲート電極11に
整合してP型ベース領域9内に設けたN型ソース領域1
0と、N型エピタキシャル層4内の素子分離層5に接し
て設けたN型不純物を高濃度にドープしたN+ 型拡散層
6と、N型ソース領域10とP型ウェル8を接続するソ
ース電極12と、素子分離層5に接続する引出電極13
と、N型シリコン基板1の下面に設けたドレイン電極1
4を有して構成されている。
As shown in FIG. 1, an N-type impurity is selectively diffused in the P-type epitaxial layer 2 provided on the N-type silicon substrate 1 and connected to the N-type silicon substrate 1.
Type buried diffusion layer 3 and N provided on the surface including the N type buried layer 3
Type epitaxial layer 4, P type element isolation layer 5 provided on N type epitaxial layer 4 and reaching P type epitaxial layer 2, and P type base region 9 provided in an element formation region partitioned by element isolation layer 5. And the N-type source region 1 provided in the P-type base region 9 in alignment with the P-type well 8 and the gate electrode 11 provided on the P-type base region 9 via the insulating film 7.
0, an N + type diffusion layer 6 provided in contact with the element isolation layer 5 in the N type epitaxial layer 4 and heavily doped with N type impurities, a source connecting the N type source region 10 and the P type well 8 Electrode 12 and extraction electrode 13 connected to element isolation layer 5
And the drain electrode 1 provided on the lower surface of the N-type silicon substrate 1.
4 is configured.

【0015】ここで、N+ 型拡散層6と素子分離層5の
間に作られるダイオードはP型ベース領域9とN型エピ
タキシャル層4の間に作られるダイオードよりも逆耐圧
が低くなる様に作られる。
Here, the diode formed between the N + type diffusion layer 6 and the element isolation layer 5 has a lower reverse breakdown voltage than the diode formed between the P type base region 9 and the N type epitaxial layer 4. Made

【0016】本実施例のパワーICの縦型MOSトラン
ジスタに、誘電性負荷を接続した場合の動作は図4に示
す等価回路のトランジスタQ1 がオフしたあと、ドレイ
ン電極14の電位が上昇していくと、ダイオードD1
2 には逆バイアスがかかっていく。本実施例では、N
+ 型拡散層6によってダイオードD2 の逆耐圧はダイオ
ードD1 よりも低く設計されているため、先にダイオー
ドD2 がブレークダウンしてI4 が流れ始める。I4
流れることで、I2 ,I3 は殆ど流れず、よってNPN
トランジスタQ2 のベースがバイアスされないため、ト
ランジスタの破壊がおこらない。
When a dielectric load is connected to the vertical MOS transistor of the power IC of this embodiment, the operation of the equivalent circuit shown in FIG. 4 is such that the transistor Q 1 is turned off and the potential of the drain electrode 14 rises. As you go, the diode D 1 ,
Reverse bias is applied to D 2 . In this embodiment, N
+ Since the inverse breakdown voltage of the diode D 2 by type diffusion layer 6 is designed to be lower than the diode D 1, above the diode D 2 begins I 4 to break down the flow. Since I 4 flows, I 2 and I 3 hardly flow, and thus the NPN
Since the base of the transistor Q 2 is not biased, the transistor will not be destroyed.

【0017】図2は本発明の第2の実施例を示す断面図
である。
FIG. 2 is a sectional view showing a second embodiment of the present invention.

【0018】図2に示すように、図1のN+ 型拡散層6
の代りにN+ 型埋込拡散層15をP型エピタキシャル層
2に設けてN型埋込拡散層3と素子分離層5との間でダ
イオードD2 を形成している以外は第1の実施例と同様
の構成を示しており、第1の実施例と同様の効果を有す
る。
As shown in FIG. 2, the N + type diffusion layer 6 of FIG.
In the first embodiment except that the N + type buried diffusion layer 15 is provided in the P type epitaxial layer 2 instead of the above to form the diode D 2 between the N type buried diffusion layer 3 and the element isolation layer 5. The structure is similar to that of the example, and has the same effect as that of the first embodiment.

【0019】[0019]

【発明の効果】以上説明したように本発明は、縦型MO
SFETの外周部に、耐圧の低いダイオードを作り込む
ことによって、誘導性負荷を駆動するときに生ずる逆起
電力によるトランジスタの破壊を防止することができる
という効果を有する。
As described above, according to the present invention, the vertical MO
By forming a diode having a low breakdown voltage on the outer peripheral portion of the SFET, it is possible to prevent the breakdown of the transistor due to the counter electromotive force generated when driving the inductive load.

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

【図1】本発明の第1の実施例を示す断面図。FIG. 1 is a sectional view showing a first embodiment of the present invention.

【図2】本発明の第2の実施例を示す断面図。FIG. 2 is a sectional view showing a second embodiment of the present invention.

【図3】従来の半導体装置の一例を示す断面図。FIG. 3 is a sectional view showing an example of a conventional semiconductor device.

【図4】縦型MOSFETの等価回路図。FIG. 4 is an equivalent circuit diagram of a vertical MOSFET.

【符号の説明】[Explanation of symbols]

1 N型シリコン基板 2 P型エピタキシャル層 3 N型埋込拡散層 4 N型エピタキシャル層 5 素子分離層 6 N+ 型拡散層 7 P型ベース領域 8 P型ウェル 9 P型ベース領域 10 N型ソース領域 11 ゲート電極 12 ソース電極 13 引出電極 14 ドレイン電極 15 N+ 型埋込拡散層1 N-type silicon substrate 2 P-type epitaxial layer 3 N-type buried diffusion layer 4 N-type epitaxial layer 5 Element isolation layer 6 N + type diffusion layer 7 P-type base region 8 P-type well 9 P-type base region 10 N-type source Region 11 Gate electrode 12 Source electrode 13 Extraction electrode 14 Drain electrode 15 N + type buried diffusion layer

Claims (2)

【特許請求の範囲】[Claims] 【請求項1】 一導電型半導体基板の一主面に設けた逆
導電型エピタキシャル層と、前記逆導電型エピタキシャ
ル層に設けて前記半導体基板に達する一導電型埋込拡散
層と、前記一導電型拡散層を含む表面に設けた一導電型
エピタキシャル層と、前記一導電型エピタキシャル層に
設けて前記逆導電型エピタキシャル層に達する逆導電型
の素子分離層と、前記素子分離層で分離された前記一導
電型エピタキシャル層内に設けた逆導電型のベース領域
と、前記ベース領域内に設けた一導電型のソース領域と
を有する半導体装置において、分離された前記一導電型
エピタキシャル層内の前記素子分離層に接して設けた一
導電型の高濃度拡散層を有することを特徴とする半導体
装置。
1. A reverse conductivity type epitaxial layer provided on one main surface of a conductivity type semiconductor substrate, a buried conductivity diffusion layer reaching the semiconductor substrate by being provided on the reverse conductivity type epitaxial layer, and the conductivity type. The one conductivity type epitaxial layer provided on the surface including the type diffusion layer, the opposite conductivity type element isolation layer which is provided on the one conductivity type epitaxial layer and reaches the opposite conductivity type epitaxial layer, and the element isolation layer In a semiconductor device having a base region of opposite conductivity type provided in the one conductivity type epitaxial layer and a source region of one conductivity type provided in the base region, the semiconductor device in the separated one conductivity type epitaxial layer A semiconductor device having a high-concentration diffusion layer of one conductivity type provided in contact with an element isolation layer.
【請求項2】 一導電型半導体基板の一主面に設けた逆
導電型エピタキシャル層と、前記逆導電型エピタキシャ
ル層に設けて前記半導体基板に達する一導電型埋込拡散
層と、前記一導電型拡散層を含む表面に設けた一導電型
エピタキシャル層と、前記一導電型エピタキシャル層に
設けて前記逆導電型エピタキシャル層に達する逆導電型
の素子分離層と、前記素子分離層で分離された前記一導
電型エピタキシャル層内に設けた逆導電型のベース領域
と、前記ベース領域内に設けた一導電型のソース領域と
を有する半導体装置において、前記逆導電型エピタキシ
ャル層内の前記一導電型埋込拡散層及び前記素子分離層
に接して設けた一導電型の高濃度埋込拡散層を有するこ
とを特徴とする半導体装置。
2. An opposite conductivity type epitaxial layer provided on one main surface of a one conductivity type semiconductor substrate, one conductivity type buried diffusion layer reaching the semiconductor substrate by being provided on the opposite conductivity type epitaxial layer, and the one conductivity type. The one conductivity type epitaxial layer provided on the surface including the type diffusion layer, the opposite conductivity type element isolation layer which is provided on the one conductivity type epitaxial layer and reaches the opposite conductivity type epitaxial layer, and the element isolation layer A semiconductor device having a base region of opposite conductivity type provided in the epitaxial layer of one conductivity type and a source region of one conductivity type provided in the base region, wherein the one conductivity type in the epitaxial layer of the opposite conductivity type A semiconductor device comprising a buried diffusion layer and a high conductivity buried diffusion layer of one conductivity type provided in contact with the element isolation layer.
JP28804892A 1992-10-27 1992-10-27 Semiconductor device Expired - Fee Related JP2871352B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP28804892A JP2871352B2 (en) 1992-10-27 1992-10-27 Semiconductor device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP28804892A JP2871352B2 (en) 1992-10-27 1992-10-27 Semiconductor device

Publications (2)

Publication Number Publication Date
JPH06140632A true JPH06140632A (en) 1994-05-20
JP2871352B2 JP2871352B2 (en) 1999-03-17

Family

ID=17725164

Family Applications (1)

Application Number Title Priority Date Filing Date
JP28804892A Expired - Fee Related JP2871352B2 (en) 1992-10-27 1992-10-27 Semiconductor device

Country Status (1)

Country Link
JP (1) JP2871352B2 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1022785A1 (en) * 1999-01-25 2000-07-26 STMicroelectronics S.r.l. Electronic semiconductor power device with integrated diode
KR100648276B1 (en) * 2004-12-15 2006-11-23 삼성전자주식회사 Vdmos device incorporating reverse diode
US7936003B2 (en) 2005-02-03 2011-05-03 Samsung Electronics Co., Ltd. Semiconductor device having transistor with vertical gate electrode and method of fabricating the same

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1022785A1 (en) * 1999-01-25 2000-07-26 STMicroelectronics S.r.l. Electronic semiconductor power device with integrated diode
US6222248B1 (en) 1999-01-25 2001-04-24 Stmicroelectronics S.R.L. Electronic semiconductor power device with integrated diode
USRE40222E1 (en) * 1999-01-25 2008-04-08 Stmicroelectronics S.R.L. Electronic semiconductor power device with integrated diode
KR100648276B1 (en) * 2004-12-15 2006-11-23 삼성전자주식회사 Vdmos device incorporating reverse diode
US7417282B2 (en) 2004-12-15 2008-08-26 Samsung Electronics, Co., Ltd. Vertical double-diffused metal oxide semiconductor (VDMOS) device incorporating reverse diode
US7936003B2 (en) 2005-02-03 2011-05-03 Samsung Electronics Co., Ltd. Semiconductor device having transistor with vertical gate electrode and method of fabricating the same

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