Ngk Insulators, Inc.

Sota Maehara

Mikiya Ichimura

Yoshitaka Kuraoka

Mitsuhiro Tanaka

Makoto Miyoshi

Shigeaki Sumiya

Tomohiko Sugiyama

An epitaxial substrate for semiconductor elements suppresses leakage current and has a high breakdown voltage. The epitaxial substrate for semiconductor elements includes: a semi-insulating free-standing substrate formed of GaN doped with Zn; a buffer layer formed of a group 13 nitride adjacent to the free-standing substrate; a channel layer formed of a group 13 nitride adjacent to the buffer layer; and a barrier layer formed of a group 13 nitride on an opposite side of the buffer layer with the channel layer therebetween, wherein part of a first region consisting of the free-standing substrate and the buffer layer is a second region containing Si at a concentration of 1&#xd7;10cmor more, and a minimum value of a concentration of Zn in the second region is 1&#xd7;10cm.

Epitaxial substrate for semiconductor elements, semiconductor element, and manufacturing method for epitaxial substrates for semiconductor elements

An epitaxial substrate for semiconductor elements is provided which suppresses the occurrence of current collapse. The epitaxial substrate for the semiconductor elements includes: a semi-insulating free-standing substrate formed of GaN doped with Zn; a buffer layer adjacent to the free-standing substrate; a channel layer adjacent to the buffer layer; and a barrier layer provided on an opposite side of the buffer layer with the channel layer therebetween, wherein the buffer layer is a diffusion suppressing layer formed of AlGaN (0.7&#x2264;p&#x2264;1) and suppresses diffusion of Zn from the free-standing substrate into the channel layer.

Provided is an epitaxial substrate for semiconductor elements which suppresses an occurrence of current collapse. The epitaxial substrate for the semiconductor elements includes: a semi-insulating free-standing substrate formed of GaN being doped with Zn; a buffer layer being adjacent to the free-standing substrate; a channel layer being adjacent to the buffer layer; and a barrier layer being provided on an opposite side of the buffer layer with the channel layer therebetween, wherein the buffer layer is a diffusion suppressing layer formed of Al-doped GaN and suppresses diffusion of Zn from the free-standing substrate into the channel layer.

An epitaxial substrate for semiconductor elements which suppresses the occurrence of current collapse. The epitaxial substrate for the semiconductor elements includes: a semi-insulating free-standing substrate formed of GaN doped with Zn; a buffer layer adjacent to the free-standing substrate; a channel layer adjacent to the buffer layer; and a barrier layer provided on an opposite side of the buffer layer with the channel layer provided therebetween, wherein the buffer layer is a diffusion suppressing layer that suppresses the diffusion of Zn from the free-standing substrate into the channel layer.

Provided is a group 13 nitride epitaxial substrate with which the HEMT device having superior characteristics can be manufactured. This epitaxial substrate is provided with: a base substrate composed of SiC and having a main surface with a (0001) plane orientation; a nucleation layer formed on one main surface of the base substrate and composed of AlN; an electron transit layer formed on the nucleation layer and composed of a group 13 nitride with the composition AlGaN (0&#x2264;y&#x3c;1); and a barrier layer formed on the electron transit layer and composed of a group 13 nitride with the composition InAlN (0.13&#x2264;z&#x2264;0.23) or AlGaN (0.15&#x2264;w&#x2264;0.35). The (0001) plane of the base substrate has an off angle of 0.1&#xb0; or more and 0.5&#xb0; or less, and an intermediate layer composed of a group 13 nitride with the composition AlGaN (0.01 &#x2264;x&#x2264;0.4) is further provided between the nucleation layer and the electron transit layer.

Epitaxial substrate for semiconductor device and method for manufacturing same

Provided is a semiconductor device in which a reverse leakage current is suppressed and the mobility of a two-dimensional electron gas is high. A semiconductor device includes: an epitaxial substrate in which a group of group-III nitride layers are laminated on a base substrate such that a (0001) crystal plane is substantially in parallel with a substrate surface; and a Schottky electrode. The epitaxial 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 intermediate layer made of GaN adjacent to the barrier layer; and a cap layer made of AlN and adjacent to the intermediate layer. A Schottky electrode is bonded to the cap layer.

Semiconductor device, HEMT device, and method of manufacturing semiconductor device

Provided is a method for treating a group III nitride substrate capable of obtaining, in the case where a group III nitride layer is laminated thereon, a group III nitride substrate that can form an electronic device having excellent characteristics. The method for treating a group III nitride substrate includes the steps of CMPing a surface of a substrate, elevating a temperature of the group III nitride substrate after the CMP process to a predetermined annealing temperature under a nitrogen gas atmosphere, and holding the group III nitride substrate whose temperature has been elevated to the annealing temperature for four minutes or more and eight minutes or less in a first mixed atmosphere of a hydrogen gas and a nitrogen gas or a second mixed atmosphere of a hydrogen gas and an ammonia gas.

Method for treating group III nitride substrate and method for manufacturing epitaxial substrate

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 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.

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

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 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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Nagoya, Japan

Sota Maehara