Denso Corporation

Nippondenso Co., Ltd.

Yasushi Higuchi

Hiroyuki Yamane

Tetsuo Fujii

Kazuhiro Oyama

Masakiyo Sumitomo

Shinichi Hoshi

Youngshin Eum

Ryoichi Kubokoya

Yoshiyuki Hattori

Shigeki Takahashi

Nozomu Akagi

Makoto Kuwahara

Takashi Nakano

Mitsutaka Katada

Shigemitsu Fukatsu

Noriyuki Iwamori

Takeshi Kuzuhara

Tsutomu Kawaguchi

Masaki Matsui

Kyoko Okada

Seigo Oosawa

Yoshinori Tsuchiya

Kazunori Kawamoto

A semiconductor device includes a conductive substrate, a channel forming layer, a first electrode, and a second electrode. The channel forming layer is located above the conductive substrate and includes at least one hetero-junction structure. The hetero-junction structure includes a first GaN-type semiconductor layer providing a drift region and a second GaN-type semiconductor layer having a bandgap energy greater than the first GaN-type semiconductor layer. A total fixed charge quantity of charges in the first GaN-type layer and the second GaN-type layer is from 0.5&#xd7;10to 1.5&#xd7;10cm. The charges in the first GaN-type layer and the second GaN-type layer include charges generated by the polarization in the first GaN-type layer. Accordingly, the semiconductor device capable of improving a break-down voltage and decreasing an on-resistance is obtained.

Semiconductor device

A nitride semiconductor device includes a horizontal switching device that includes a substrate, a channel forming layer, a source region, a drain region and a gate region. The source region and the drain region are arranged apart from each other in one direction along a plane of the substrate. The gate region is formed of a p-type semiconductor layer and is arranged between the source region and the drain region. The gate region is divided into multiple parts in a perpendicular direction along the plane of the substrate, the perpendicular direction being perpendicular to an arrangement direction in which the source region and the drain region are arranged. Accordingly, on-resistance is decreased while securing high breakdown voltage.

Nitride semiconductor device including a horizontal switching device

A semiconductor device includes a lateral switching device having: a substrate; a channel forming layer that has a heterojunction structure made of a GaN layer and an AlGaN layer and is formed with a recessed portion, on the substrate; a gate structure part that includes a gate insulating film and a gate electrode formed in the recessed portion; and a source electrode and a drain electrode on opposite sides of the gate structure part on the channel forming layer. The AlGaN layer includes a first AlGaN layer that has an Al mixed crystal ratio determining a two dimensional electron gas density, and a second AlGaN layer that has an Al mixed crystal ratio smaller than that of the first AlGaN layer to induce negative fixed charge, and is disposed in contact with the gate structure part and spaced from the source electrode and the drain electrode.

In a semiconductor device, an AlGaN layer includes a first AlGaN layer and a second AlGaN layer. The second AlGaN layer is positioned between a gate structure portion and a drain electrode and is divided into multiple parts in an arrangement direction in which the gate structure portion and the drain electrode are arranged. A second Al mixed crystal ratio of the second AlGaN layer is less than a first Al mixed crystal ratio of the first AlGaN layer. Accordingly, the semiconductor device is a normally-off-type device and is capable of restricting a decrease of a breakdown voltage and an increase of an on-resistance.

In a trench-gate-type insulated gate bipolar transistor, a current will not flow down to a lower portion of a trench, a high electrical field at the lower portion of the trench is suppressed even if a high voltage is applied, such as at a time of turning off, an increase in on-state resistance and a decrease in breakdown resistance and withstand voltage are suppressed. In the semiconductor device, a plurality of trenches is disposed to reach a rear surface of a drift layer, and a collector layer is disposed at a tip end side in an extended direction of the trenches in a surface layer portion of the drift layer. When a gate electrode is applied with a predetermined voltage, a channel region is formed in a portion of the base layer contacting the trenches, and an electric current flows in the predetermined direction along the trenches.

Trench-gate-type insulated gate bipolar transistor

In a semiconductor device, a trench gate has a bottom portion in a drift layer and a communication portion extending from a surface of a base layer to communicate with the bottom portion. A distance between adjacent bottom portions is smaller than a distance between adjacent communication portions in a x-direction. A region between adjacent trench gates is divided in a y-direction into an effective region as an electron injection source and an ineffective region which does not serve as the electron injection source. An interval L(&#x3e;0) of the ineffective region in the y-direction, a length Dof the communication portion in the z-direction, and a length Dof the bottom portion in the z-direction satisfy L&#x2266;2(D+D). The z-direction is orthogonal to a x-y plane defined by the x-direction and the y-direction which are orthogonal to each other.

Load-short-circuit-tolerant semiconductor device having trench gates

A semiconductor device includes a drift layer, a base layer on the drift layer, and trench gate structures. Each trench gate structure includes a trench reaching the drift layer by penetrating the base layer, a gate insulation layer on a wall surface of the trench, and a gate electrode on the gate insulation layer. A bottom portion of the trench gate structure is located in the drift layer and expands in a predetermined direction so that a distance between the bottom portions of adjacent trench gate structures is less than a distance between opening portions of adjacent trench gate structures in the direction. A thickness of the gate insulation layer is greater in the bottom portion than in the opening portion.

Semiconductor device and method of manufacturing the same

A semiconductor apparatus comprises: a semiconductor substrate; and a lateral type MIS transistor disposed on a surface part of the semiconductor substrate. The lateral type MIS transistor includes: a line coupled with a gate of the lateral type MIS transistor; a polycrystalline silicon resistor that is provided in the line, and that has a conductivity type opposite to a drain of the lateral type MIS transistor; and an insulating layer through which a drain voltage of the lateral type MIS transistor is applied to the polycrystalline silicon resistor.

Semiconductor apparatus having lateral type MIS transistor

A semiconductor device includes: a semiconductor substrate; a lateral MOS transistor disposed in the substrate; a Zener diode disposed in the substrate; and a capacitor disposed in the substrate. The transistor includes a drain and a gate, and the diode and the capacitor are coupled in series between the drain and the gate. This device has minimized dimensions and high switching speed. Further, both of a switching loss and a surge voltage are improved.

Semiconductor device having lateral MOS transistor and zener diode

A semiconductor device having an enhancement-type MOS structure which can prevent large leakage current is disclosed. A high-concentration region for threshold-value regulation use formed in a channel region below a gate electrode in an enhancement-type transistor is caused to be contiguous with a source region and not contiguous with a drain region. Herein, the distance between the high-concentration region and the drain region is set so as to preclude the depletion layer extending from the drain region side from reaching the high-concentration region. Therefore, the electrical field in the depletion layer does not become the critical field which causes avalanche or Zener breakdown, and so leakage current can be caused to be reduced.

Semiconductor device and fabrication process thereof

Enhancement-type semiconductor having reduced leakage current

A high withstanding voltage MIS transistor, including an offset region and a double offset region in a region of a semiconductor substrate. The region of the semiconductor substrate has a first conductivity type. The offset region connects to a drain region, and has a second conductivity type. An impurity concentration of the offset region is lower than that of the drain region. The double offset region has the first conductivity type. At least a portion of the double offset region overlaps with the offset region. An impurity concentration of the double offset region is higher than that of the region of the semiconductor substrate. The disclosed structure has an improved current gain of the MIS transistor is improved. A method of manufacturing a CMOS having such a MIS transistor decreases the number of the manufacturing steps because the double offset region of a first conductivity type channel MIS transistor and the offset region of a second conductivity type channel MIS transistor are simultaneously formed.

Method of manufacturing a complementary MIS transistor

A high withstanding voltage MIS transistor, including an offset region and a double offset region in a region of a semiconductor substrate. The region of the semiconductor substrate has a first conductivity type. The offset region connects to a drain region, and has a second conductivity type. An impurity concentration of the offset region is lower than that of the drain region. The double offset region has the first conductivity type. At least a portion of the double offset region overlaps with the offset region. An impurity concentration of the double offset region is higher than that of the region of the semiconductor substrate. The disclosed structure has an improved current gain of the MIS transistor is improved.

High withstanding voltage MIS transistor

A method of producing a MIS transistor such as a MOS transistor has a P type and an N type channel transistors. P type and N type well regions are provided with the N type and the P type channel transistors, respectively. Both the P type and the N type well regions are covered with an insulating film on which gate electrodes are formed in a predetermined pattern by means of a photo-resist. This photo-resist is used as a channelling block layer when an N type impurity is implanted into the P type well region near the gate electrode so as to form an N type diffusion layer. As a result, the photo-resist prevents the N type impurity from channelling into the gate electrode so that a leak current does not occur within the P type well region of the N type channel transistor.

Method of producing a complementary-type semiconductor device

A method of manufacturing a semiconductor apparatus having a plurality of elements formed on a substrate comprises forming a pad oxidized film on the surface of the semiconductor substrate, forming a pattern of silicon nitride film to coat device areas on the pad oxidized film, and injecting boron ions into that surface of the pad oxidized film where no silicon nitride film is present, thereby to form a channel stopper region. Using the pattern of the silicon nitride film as a mask, a heat oxidized film is then formed on an elements separating region by heat oxidization, and ions of Si, N, C, or the like are injected into the surface of the heat oxidized film with such an acceleration energy that the ions are not injected into the silicon nitride film thereby to change the quality of the heat oxidized film. The silicon nitride film is removed by etching and the heat oxidized film is etching-treated by a solution of the hydrofluoric acid group to etching-remove particularly the bird's beak portions each of which is present along and under the peripheral rim of an element area of the silicon nitride film.

Growing community of inventors

Okazaki, Japan

Yasushi Higuchi