Ngk Insulators, Inc.

Nissan Motor Company Limited

Fujitsu Corporation

Other

Eudyna Devices Inc.

Makoto Miyoshi

Mitsuhiro Tanaka

Mikiya Ichimura

Shigeaki Sumiya

Yoshitaka Kuraoka

Masakazu Kobayashi

Yuichiro Imanishi

Kazuhiko Shinohara

Keiko Kushibiki

Kenji Furuya

Koh Uchida

Tomohiko Sugiyama

Takashi Kurihara

Tetsuo Watanabe

Sota Maehara

Kazuya Sasaki

Shinichi Aoki

Kenichi Kobayashi

Minoru Imaeda

Masahiro Sakai

Yasuhiro Shiraishi

Yasunori Nagakubo

Setsuo Misaizu

Yasuhiro Tanaka

Hiroo Kitasagami

Takashi Egawa

Akihiko Hayashi

Kakuji Inoue

Masahiko Yamashita

Masato Hino

Shinya Suzuki

Hirokazu Osada

Hirohide Kai

Tatsuya Nishimura

Kazuhisa Kogure

Shinichiro Sano

Takayoshi Ikegami

Hiroyasu Ishikawa

An epitaxial substrate having preferable two dimensional electron gas characteristic and contact characteristic is provided in the present invention. A channel layer is formed on a base substrate with GaN. A spacer layer is formed on the channel layer with AlN. A barrier layer is formed on the spacer layer with group III nitride having a composition of InAlGaN (wherein x+y+z=1) and at least including In, Al, and Ga such that the composition of the barrier layer is within the range surrounded with four lines defined in accordance with the composition on a ternary phase diagram with InN, AlN, and GaN as vertexes.

Epitaxial substrate for semiconductor device, semiconductor device, and method of manufacturing epitaxial substrate for semiconductor device

A semiconductor device having small leakage current and high breakdown voltage during reverse blocking, small on-state resistance and large output current at forward conduction, short reverse recovery time at shutoff, and high peak surge current value is provided. An n-type layer is made of a group-III nitride, and a p-type layer is made of a group-IV semiconductor material having a smaller band gap than the group-III nitride. The energy level at the top of the valence band of the n-type layer is lower than the energy level at the top of the valence band of the p-type layer, so that a P-N junction semiconductor device satisfying the above requirements is obtained. Further, a combined structure of P-N junction and Schottky junction by additionally providing an anode electrode to be in Schottky contact with the n-type layer also achieves the effect of decreasing voltage at the rising edge of current resulting from the Schottky junction.

Semiconductor device

Provided is a crack-free epitaxial substrate with reduced warping, in which a silicon substrate is used as a base substrate. The epitaxial substrate includes a (111) single crystal Si substrate, a superlattice layer group in which a plurality of superlattice layers are laminated, and a crystal layer. The superlattice layer is formed of a first unit layer and a second unit layer made of group-III nitrides having different compositions being alternately and repeatedly laminated. The crystal layer is made of a group-III nitride and formed above the base substrate so as to be positioned at an upper side of the superlattice layer group relative to the base substrate. The superlattice layer group has a compressive strain contained therein. In the superlattice layer group, the more distant the superlattice layer is from the base substrate, the greater the compressive strain becomes.

Epitaxial substrate comprising a superlattice group and method for manufacturing the epitaxial substrate

Provided is an epitaxial substrate for use in a semiconductor element, having excellent characteristics and capable of suitably suppressing diffusion of elements from a cap layer. An epitaxial substrate for use in a semiconductor element, in which a group of group-III nitride layers are laminated on a base substrate such that a (0001) crystal plane of the group of group-III nitride layers is substantially in parallel with a substrate surface of the base substrate, includes: a channel layer made of a first group-III nitride having a composition of InAlGaN (x1+y1+z1=1, z1&#x3e;0); a barrier layer made of a second group-III nitride having a composition of InAlN (x2+y2=1, x2&#x3e;0, y2&#x3e;0); an anti-diffusion layer made of AlN and having a thickness of 3 nm or more; and a cap layer made of a third group-III nitride having a composition of InAlGaN (x3+y3+z3=1, z3&#x3e;0).

Epitaxial substrate for semiconductor element, semiconductor element, PN junction diode, and method for manufacturing an epitaxial substrate for semiconductor element

Provided is a crack-free epitaxial substrate having a small amount of warping, in which a silicon substrate is used as a base substrate. The epitaxial substrate includes: a (111) single crystal Si substrate and a buffer layer formed of a plurality of lamination units being continuously laminated. The lamination unit includes: a composition modulation layer formed of a first and a second unit layer having different compositions being alternately and repeatedly laminated such that a compressive strain exists therein; a termination layer formed on an uppermost portion of the composition modulation layer, the termination layer acting to maintain the compressive strain existing in the composition modulation layer; and a strain reinforcing layer formed on the termination layer, the strain reinforcing layer acting to enhance the compressive strain existing in the composition modulation layer.

Epitaxial substrate and method for manufacturing epitaxial substrate

Provided is a crack-free epitaxial substrate having excellent breakdown voltage properties in which a silicon substrate is used as a base. The epitaxial substrate includes a (111) single crystal Si substrate and a buffer layer including a plurality of first lamination units. Each of those units includes a composition modulation layer formed of a first composition layer made of AlN and a second composition layer made of AlGaN being alternately laminated, and a first intermediate layer made of AlGaN (0&#x2266;y&#x3c;1). The relationship of x(1)&#x2267;x(2)&#x2267; . . . &#x2267;x(n&#x2212;1)&#x2267;x(n) and x(1)&#x3e;x(n) is satisfied, where n represents the number of laminations of each of the first and second composition layers, and x(i) represents the value of x in i-th one of the second composition layers as counted from the base substrate side. The second composition layer is coherent to the first composition layer, and the first intermediate layer is coherent to the composition modulation layer.

Provided is an epitaxial substrate capable of manufacturing a HEMT device that has excellent two-dimensional electron gas characteristics and is capable of performing normally-off operation. A channel layer is formed of a first group III nitride represented by InAlGaN (x1+y1+z1=1) so as to have a composition in a range determined by x1=0 and 0&#x2266;y1&#x2266;0.3. A barrier layer is formed of a second group III nitride represented by InAlGaN (x2+y2+z2=1) so as to have a composition, in a ternary phase diagram with InN, AlN and GaN being vertices, in a range surrounded by four straight lines determined in accordance with the composition (AlN molar fraction) of the first group III nitride and to have a thickness of 5 nm or less.

Group III nitride epitaxial substrate for semiconductor device, semiconductor device, and process for producing group III nitride epitaxial substrate for semiconductor device

Provided is an epitaxial substrate having excellent two-dimensional electron gas characteristics and reduced internal stress due to strains. A channel layer is formed of a first group III nitride represented by InAlGaN (x1+y1+z1=1) so as to have a composition in a range determined by x1=0 and 0&#x2266;y1&#x2266;0.3. A barrier layer is formed of a second group III nitride represented by InAlGaN (x2+y2+z2=1) so as to have a composition, in a ternary phase diagram with InN, AlN and GaN being vertices, in a range surrounded by five straight lines determined in accordance with the composition (AlN molar fraction) of the first group III nitride.

Provided is a semiconductor device of normally-off operation type having a low on-resistance. An epitaxial substrate for it includes: a base substrate; a channel layer made of a first group-III nitride having a composition of InAlGaN at least containing Al and Ga and x1=0 and 0&#x2266;y1&#x2266;0.3; and a barrier layer made of a second group-III nitride having a composition of InAlGaN at least containing In and Al. The composition of the second group-III nitride is, in a ternary phase diagram for InN, AlN, and GaN, in a certain range that is determined in accordance with the composition of the first group-III nitride. The barrier layer has a thickness of 3 nm or less. A low-crystallinity insulating layer is further formed on the barrier layer. The low-crystallinity insulating layer is made of silicon nitride and has a thickness of 3 nm or less.

Epitaxial substrate for semiconductor device, semiconductor device, method of manufacturing epitaxial substrate for semiconductor device, and method of manufacturing semiconductor device

Provided is an epitaxial substrate for a semiconductor device, which has excellent schottky contact characteristics that are stable over time. The epitaxial substrate for a semiconductor device includes a base substrate, a channel layer formed of a first group III nitride containing at least Ga and having a composition of InAlGaN (x1+y1+z1=1), and a barrier layer formed of a second group III nitride containing at least In and Al and having a composition of InAlGaN (x2+y2+z2=1), wherein the barrier layer has tensile strains in an in-plane direction, and pits are formed on a surface of the barrier layer at a surface density of 5&#xd7;10/cmor more and 1&#xd7;10/cmor less.

Epitaxial substrate for semiconductor device and semiconductor device

An epitaxial substrate, in which a group of group-III nitride layers is formed on a single-crystal silicon substrate so that a crystal plane is approximately parallel to a substrate surface, comprises: a first group-III nitride layer formed of AlN on the base substrate; a second group-III nitride layer formed of InAlGaN (xx+yy+zz=1, 0&#x2266;xx&#x2266;1, 0&#x3c;yy&#x2266;1 and 0&#x3c;zz&#x2266;1) on the first group-III nitride layer; and at least one third group-III nitride layer epitaxially-formed on the second group-III nitride layer, wherein: the first group-III nitride layer is a layer containing multiple defects including at least one type of a columnar crystal, a granular crystal, a columnar domain and a granular domain; and an interface between the first group-III nitride layer and the second group-III nitride layer is a three-dimensional asperity surface.

Epitaxial substrate for semiconductor device, method for manufacturing epitaxial substrate for semiconductor device, and semiconductor device

Provided is a crack-free epitaxial substrate having a small amount of dislocations in which a silicon substrate is used as a base substrate. An epitaxial substrate includes a substrate made of (111) single crystal silicon and a base layer group in which a plurality of base layers are laminated. Each of the plurality of base layers includes a first group-III nitride layer made of AlN and a second group-III nitride layer made of AlGaN formed on the first group-III nitride layer. The first group-III nitride layer has many crystal defects. An interface between the first and second group-III nitride layers is a three-dimensional concavo-convex surface. In the base layer other than the base layer formed immediately above the base substrate, the first group-III nitride layer has a thickness of 50 nm or more and 100 nm or less and the second group-III nitride layer satisfies 0&#x2266;yy&#x2266;0.2.

Provided is a crack-free epitaxial substrate having excellent breakdown voltage properties in which a silicon substrate is used as a base substrate thereof. The epitaxial substrate includes: a (111) single crystal Si substrate and a buffer layer including a plurality of composition modulation layers each formed of a first composition layer made of AlN and a second composition layer made of AlGaN (0&#x2266;x&#x3c;1) being alternately laminated. The relationship of x(1)&#x2267;x(2)&#x2267; . . . &#x2267;x(n&#x2212;1)&#x2267;x(n) and x(1)&#x3e;x(n) is satisfied, where n represents the number of laminations of each of the first and the second composition layer, and x(i) represents the value of x in i-th one of the second composition layers as counted from the base substrate side. Each of the second composition layers is formed so as to be in a coherent state relative to the first composition layer.

Provided is an epitaxial substrate for semiconductor device that is capable of achieving a semiconductor device having high reliability in reverse characteristics of schottky junction. An epitaxial substrate for semiconductor device obtained by forming, on a base substrate, a group of group III nitride layers by lamination such that a (0001) crystal plane of each layer is approximately parallel to a substrate surface includes: a channel layer formed of a first group III nitride having a composition of InAlGaN (x1+y1+z1=1, z1&#x3e;0); and a barrier layer formed of a second group III nitride having a composition of InAlN (x2+y2=1, x2&#x3e;0, y2&#x3e;0), wherein the second group III nitride is a short-range-ordered mixed crystal having a short-range order parameter &#x3b1; satisfying a range where 0&#x2266;&#x3b1;&#x2266;1.

Epitaxial substrate for semiconductor device, schottky junction structure, and leakage current suppression method for schottky junction structure

Provided is a crack-free epitaxial substrate having a small amount of warping, in which a silicon substrate is used as a base substrate. The epitaxial substrate includes a (111) single crystal Si substrate, a buffer layer, and a crystal layer. The buffer layer is formed of a first lamination unit and a second lamination unit being alternately laminated. The first lamination unit includes a composition modulation layer and a first intermediate layer. The composition modulation layer is formed of a first unit layer and a second unit layer having different compositions being alternately and repeatedly laminated so that a compressive strain exists therein. The first intermediate layer enhances the compressive strain existing in the composition modulation layer. The second lamination unit is a second intermediate layer that is substantially strain-free.

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Inazawa, Japan

Makoto Miyoshi