Semiconductor Components Industries, LLC

Sanyo Electric Co., Ltd.

Sanyo Semiconductor Co., Ltd.

On Semiconductor Trading, Ltd.

Yasuhiro Takeda

Seiji Otake

Shuichi Kikuchi

Shinya Inoue

Yuta Miyamoto

Yuzo Otsuru

Kazunori Fujita

Satoru Shimada

Kenichi Maki

Kiyoshi Yoneda

Ryoichi Yokoyama

Toshiyuki Ohkoda

Hideaki Fujiwara

Koji Hirosawa

Haruki Yoneda

Kazunari Honma

Kazuhiro Yoshitake

Koji Yamano

Hideharu Nagasawa

Mitsuaki Morigami

Shigeyuki Sugihara

An ESD protection element can have a high ESD protection characteristic which has a desired breakdown voltage and flows a large discharge current. A junction diode is formed by an N+ type buried layer having a proper impurity concentration and a P+ type buried layer. The P+ type buried layer is combined with a P+ type drawing layer to penetrate an N&#x2212; type epitaxial layer and be connected to an anode element. An N+ type diffusion layer and a P+ typed diffusion layer connected to an surrounding the N+ type diffusion layer are formed in the N&#x2212; epitaxial layer surrounded by the P+ type buried layer etc. The N+ type diffusion layer and P+ type diffusion layer are connected to a cathode electrode. An ESD protection element is formed by the PN junction diode and a parasitic PNP bipolar transistor which uses the P+ type diffusion layer as an emitted, the N&#x2212; type epitaxial layer as the base, and the P+ type drawing layer etc. as the collector.

Circuit including a resistive element, a diode, and a switch and a method of using the same

The invention provides an LDMOS transistor of which the time-dependent degrading of the performance due to the trapping of hot electrons in the gate insulation film is decreased. A body layer is disposed in a surface portion of an N&#x2212; type semiconductor layer. A source layer including an N&#x2212; type layer is disposed in a surface portion of the body layer. An N&#x2212; type drift layer is formed in a surface portion of the N&#x2212; type semiconductor layer. This drift layer includes a first region having a first N type impurity concentration peak region and a second region having a second N type impurity concentration peak region that is positioned deeper than the first N type impurity concentration peak region, the second region adjoining this first region. An N+ type drain layer is formed in a surface portion of the second region.

Semiconductor device and method of manufacturing the same

An N type layer made of an N type epitaxial layer in which an N+ type drain layer etc are formed is surrounded by a P type drain isolation layer extending from the front surface of the N type epitaxial layer to an N+ type buried layer. A P type collector layer is formed in an N type layer made of the N type epitaxial layer surrounded by the P type drain isolation layer and a P type element isolation layer, extending from the front surface to the inside of the N type layer. A parasitic bipolar transistor that uses the first conductive type drain isolation layer as the emitter, the second conductive type N type layer as the base, and the collector layer as the collector is thus formed so as to flow a surge current into a ground line.

LDMOS semiconductor device with parasitic bipolar transistor for reduced surge current

An ESD protection element is formed by a PN junction diode including an N+ type buried layer having a proper impurity concentration and a P+ type buried layer and a parasitic PNP bipolar transistor which uses a P+ type drawing layer connected to a P+ type diffusion layer as the emitter, an N&#x2212; type epitaxial layer as the base, and a P type semiconductor substrate as the collector. The P+ type buried layer is connected to an anode electrode, and the P+ type diffusion layer and an N+ type diffusion layer connected to and surrounding the P+ type diffusion layer are connected to a cathode electrode. When a large positive static electricity is applied to the cathode electrode, the parasitic PNP bipolar transistor turns on to flow a large discharge current.

Semiconductor device

The invention provides an LDMOS transistor of which the time-dependent degrading of the performance due to the trapping of hot electrons in the gate insulation film is decreased. A body layer is disposed in a surface portion of an N&#x2212;&#x2212; type semiconductor layer. A source layer including an N&#x2212; type layer is disposed in a surface portion of the body layer. An N&#x2212; type drift layer is formed in a surface portion of the N&#x2212;&#x2212; type semiconductor layer. This drift layer includes a first region having a first N type impurity concentration peak region and a second region having a second N type impurity concentration peak region that is positioned deeper than the first N type impurity concentration peak region, the second region adjoining this first region. An N+ type drain layer is formed in a surface portion of the second region.

A semiconductor device equally turns on the parasitic bipolar transistors in the finger portions of the finger form source and drain electrodes when a surge voltage is applied, even with the P+ type contact layer surrounding the N+ type source layers and the N+ type drain layers connected to the finger form source and drain electrodes. A P+ type contact layer surrounds N+ type source layers and N+ type drain layers. Metal silicide layers are formed on the N+ type source layers, the N+ type drain layers, and a portion of the P+ type contact layer. Finger form source electrodes, finger form drain electrodes, and a P+ type contact electrode surrounding these finger form electrodes are formed, being connected to the metal silicide layers respectively through contact holes formed in an interlayer insulation film deposited on the metal silicide layers.

An ESD protection element is formed by a PN junction diode including an N+ type buried layer having a proper impurity concentration and a first P+ type buried layer and a parasitic PNP bipolar transistor which uses a second P+ type buried layer connected to a P+ type diffusion layer as the emitter, an N&#x2212; type epitaxial layer as the base, and the first P+ type buried layer as the collector. The first P+ type buried layer is connected to an anode electrode, and the P+ type diffusion layer and an N+ type diffusion layer surrounding the P+ type diffusion layer are connected to a cathode electrode. When a large positive static electricity is applied to the cathode electrode, and the parasitic PNP bipolar transistor turns on to flow a large discharge current.

The invention prevents a source-drain breakdown voltage of a DMOS transistor from decreasing due to dielectric breakdown in a portion of a N type drift layer having high concentration formed in an active region near field oxide film corner portions surrounding an gate width end portion. The field oxide film corner portions are disposed on the outside of the gate width end portion so as to be further away from a P type body layer formed in the gate width end portion by forming the active region wider on the outside of the gate width end portion than in a gate width center portion. By this, the N type drift layer having high concentration near the field oxide film corner portions are disposed further away from the P type body layer without increasing the device area.

An ON resistance of a bidirectional switch with a trench gate structure composed of two MOS transistors sharing a common drain is reduced. A plurality of trenches is formed in an N type well layer. Then a P type body layer is formed in every other column of the N type well layer interposed between a pair of the trenches. A first N+ type source layer and a second N+ type source layer are formed alternately in each of a plurality of the P type body layers. A first gate electrode is formed in each of a pair of the trenches interposing the first N+ type source layer, and a second gate electrode is formed in each of a pair of the trenches interposing the second N+ type source layer. A portion of the N type well layer interposed between a sidewall on an opposite side of the body layer of the trench in which the first gate electrode is formed and a sidewall on an opposite side of the body layer of the trench in which the second gate electrode is formed makes an N type drain layer serving as an electric field relaxation layer. A cross-sectional area of the N type drain layer makes a path of the ON current.

Bidirectional switch

The invention provides a DMOS transistor in which a leakage current is decreased and the source-drain breakdown voltage of the transistor in the off state is enhanced when a body layer is formed by oblique ion implantation. After a photoresist layeris formed, using the photoresist layerand a gate electrodeas a mask, first ion implantation is performed toward a first corner portionCon the inside of the gate electrodein a first direction shown by an arrow A'. A first body layerA&#x2032; is formed by this first ion implantation. The first body layerA&#x2032; is formed so as to extend from the first corner portionCto under the gate electrode, and the P-type impurity concentration of the body layerA&#x2032; in the first corner portionCis higher than that of a conventional transistor.

DMOS transistor and method of manufacturing the same

A method of fabricating a semiconductor device includes a first step of forming a defect suppression film suppressing increase in a defect due to implantation of an impurity on a semiconductor substrate, a second step of forming an active region on a surface of the semiconductor substrate by implanting the impurity through the defect suppression film, a third step of removing the defect suppression film and a fourth step of forming an interface state suppression film suppressing increase in an interface state density of the active region on the active region.

Method of fabricating semiconductor device

An ON resistance of a trench gate type transistor and a withstand voltage of a planar type transistor are optimized at the same time. Each of first and second regions of a semiconductor layer is formed by epitaxial growth on each of first and second regions of a semiconductor substrate, respectively. A first buried layer is formed between the first region of the semiconductor substrate and the first region of the semiconductor layer, while a second buried layer is formed between the second region of the semiconductor substrate and the second region of the semiconductor layer. The first buried layer is formed of an Ntype first impurity-doped layer and an N type second impurity-doped layer that extends beyond the fist impurity-doped layer. The second buried layer is formed of an Ntype impurity-doped layer only. In the first region of the semiconductor layer, an impurity is diffused from a surface of the semiconductor layer deep into the semiconductor layer to form an N type third impurity-doped layer. The trench gate type transistor is formed in the first region of the semiconductor layer and the planar type transistor is formed in the second region of the semiconductor layer.

Semiconductor device optimized to increase withstand voltage and reduce on resistance

A semiconductor device includes a gate electrode formed through an insulating film in a groove having a first side surface adjacent to a source region and a base region, and a second conductive type first impurity region formed adjacent to a second side surface of the groove between the groove and a lead-out portion of a drain region existing below the base region so as to extend downward beyond a lower end of the groove.

Semiconductor device and method of fabricating semiconductor device

A semiconductor device includes a gate electrode formed through a gate insulating film provided on a first impurity region and a drift layer, and this gate electrode consists of two regions including a first conductivity type second impurity region opposed to the first impurity region and a third impurity region capable of forming a depletion layer.

This invention provides a DMOS transistor that has a reduced ON resistance and is prevented from deterioration in strength against an electrostatic discharge. An edge portion of a source layer of the DMOS transistor is disposed so as to recede from an inner corner portion of a gate electrode. A silicide layer is structured so as not to extend out of the edge portion of the source layer. That is, although the silicide layer is formed on a surface of the source layer, the silicide layer is not formed on a surface of a portion of a body layer, which is exposed between the source layer and the inner corner portion of the gate electrode. As a result, the strength against the electrostatic discharge can be improved, because an electric current flows almost uniformly through whole of the DMOS transistor without converging.

Growing community of inventors

Ogaki, Japan

Yasuhiro Takeda