Toyoda Gosei Co., Ltd.

Other

Ngk Insulators, Inc.

Osaka University

Research Development Corporation of Japan

Nagoya University

Kabushiki Kaisha Toyota Chuo Kenkyusho

Japan Science and Technology Agency

Research Development Corporation

Shiro Yamazaki

Katsuhide Manabe

Michinari Sassa

Hisaki Kato

Norikatsu Koide

Isamu Akasaki

Masayoshi Koike

Akira Mabuchi

Naoki Shibata

Masafumi Hashimoto

Makoto Iwai

Seiji Nagai

Fumio Kawamura

Takatomo Sasaki

Katsuhiro Imai

Miki Moriyama

Makoto Asai

Takayuki Sato

Koji Hirata

Yusuke Mori

Yasuhide Yakushi

Takanao Shimodaira

Junichi Umezaki

Hiroshi Amano

Shohei Kumegawa

Yasuo Kitaoka

Masashi Yoshimura

Koji Okuno

Shinya Asami

Koichi Goshonoo

Kazuyoshi Tomita

Yuta Tezen

Shuhei Higashihara

Toshio Hiramatsu

Akira Kojima

Masafumi Hasimoto

Aiko Murakami

Masato Arahira

Hideo Arahori

Yuji Yamada

The present invention suppresses anomalous growth of a Group III nitride semiconductor at the periphery of a seed substrate. The invention is directed to a method for producing a Group III nitride semiconductor including feeding a nitrogen-containing gas into a molten mixture of a Group III metal and a flux placed in a furnace, to thereby grow a Group III nitride semiconductor on a seed substrate. The oxygen concentration of the furnace internal atmosphere is elevated after the growth initiation temperature of the Group III nitride semiconductor has been achieved. In a period from the initiation of the growth to a certain timing, the oxygen concentration of the furnace internal atmosphere is controlled to 0.02 ppm or less, and thereafter, to greater than 0.02 ppm and 0.1 ppm or less.

Method for producing a group III nitride semiconductor by controlling the oxygen concentration of the furnace internal atmosphere

The seed substrate comprises a base substrate and a base layer comprising a Group III nitride semiconductor formed on the base substrate, which has a high dislocation density region and a low dislocation density region. The planar pattern of the high dislocation density region is a honeycomb pattern. A hollow exists between the base substrate and the low dislocation density region. The object layer is grown through a flux method using the seed substrate. The high dislocation density region is melted back at an initial stage of crystal growth, and thereafter, the object layer is grown on the top surface of the low dislocation density region. A cavity remains between the high dislocation density region and the object layer. The presence of the cavity and the hollow makes easy to peel the object layer from the seed substrate.

Method for producing Group III nitride semiconductor, seed substrate and Group III nitride semiconductor crystal

To reduce ungrown region or abnormal grain growth region in growing a Group III nitride semiconductor through a flux method. A seed substrate has a structure in which a Group III nitride semiconductor layer is formed on a ground substrate as a base, and a mask is formed on the Group III nitride semiconductor layer. The mask has a plurality of dotted windows in an equilateral triangular lattice pattern. A Group III nitride semiconductor is grown through flux method on the seed substrate. Carbon is placed on a lid of a crucible holing the seed substrate and a molten mixture so that carbon is not contact with the molten mixture at the start of crystal growth. Thereby, carbon is gradually added to the molten mixture as time passes. Thus, ungrown region or abnormal grain growth region is reduced in the Group III nitride semiconductor crystal grown on the seed substrate.

Method for producing Group III nitride semiconductor including growing Group III nitride semiconductor through flux method

The present invention provides a method for producing a Group III nitride semiconductor single crystal having excellent crystallinity, and a method for producing a GaN substrate having excellent crystallinity, the method including controlling melting back. Specifically, a mask layer is formed on a GaN substrate serving as a growth substrate. Then, a plurality of trenches which penetrate the mask layer and reach the GaN substrate are formed through photolithography. The obtained seed crystal and raw materials of a single crystal are fed to a crucible and subjected to treatment under pressurized and high temperature conditions. Portions of the GaN substrate exposed to the trenches undergo melting back with a flux. Through dissolution of the GaN substrate, the dimensions of the trenches increase, to provide large trenches. The GaN layer is grown from the surface of the mask layer as a starting point.

Method for producing a group III nitride semiconductor single crystal and method for producing a GaN substrate

The present invention provides a semiconductor crystal removal apparatus which realizes effective removal of a semiconductor crystal from a crucible through rapid melting of a solidified flux, and a method for producing a semiconductor crystal. The semiconductor crystal removal apparatus includes a crucible support for supporting a crucible so that the opening of the crucible is directed downward; a heater for heating the crucible supported on the crucible support; and a semiconductor crystal receiving net for receiving a semiconductor crystal falling from the opening of the crucible. The semiconductor crystal removal apparatus further includes a determination portion for determining removal of the semiconductor crystal on the basis of a change in weight through falling of the semiconductor crystal.

Semiconductor crystal removal apparatus and production method for semiconductor crystal

Provided is a method for producing a Group III nitride-based compound semiconductor having an M-plane main surface. The method employs a sapphire substrate having a main surface which is inclined by 30&#xb0; with respect to R-plane about a line of intersection Lformed by R-plane and A-plane perpendicular thereto. R-plane surfaces of the sapphire substrate are exposed, and a silicon dioxide mask is formed on the main surface of the substrate. AlN buffer layers are formed on the exposed R-plane surfaces. A GaN layer is formed on the AlN buffer layers. At an initial stage of GaN growth, the top surface of the sapphire substrate is entirely covered with the GaN layer through lateral growth. The GaN layer is grown so that the a-axis of the layer is perpendicular to the exposed R-plane surfaces of the sapphire substrate; the c-axis of the layer is parallel to the axis direction Lof the sapphire substrate; and the m-axis of the layer, which is inclined by 30&#xb0; from the a-axis thereof, is perpendicular to the main surface (inclined by 30&#xb0; from the exposed R-plane surfaces) of the sapphire substrate.

Method for producing group III nitride-based compound semiconductor, wafer, and group III nitride-based compound semiconductor device

A method for producing a Group III nitride semiconductor includes reacting a molten mixture containing at least a Group III element and an alkali metal with a gas containing at least nitrogen, to thereby grow a Group III nitride semiconductor crystal on the seed crystal. The method includes forming a template substrate including a sapphire substrate and a first Group III nitride semiconductor layer as the seed crystal which is formed by vapor phase growth and which includes a c-plane as a main plane is employed, and the template substrate is placed and maintained in the molten mixture under conditions where crystal growth of the Group III nitride semiconductor is inhibited, to thereby partially melt back a plurality of separated parts of the first Group III nitride semiconductor layer to such a depth that the sapphire substrate is partially exposed.

Method for producing group III nitride semiconductor

Objects of the present invention are to provide a method for producing a Group III nitride semiconductor single crystal, which method enables production of a Group III nitride semiconductor single crystal having a flat surface by means of a crucible having any inside diameter; to provide a self-standing substrate obtained from the Group III nitride semiconductor single crystal; and to provide a semiconductor device employing the self-standing substrate. The production method includes adding the template, a flux, and semiconductor raw materials to a crucible and growing a Group III nitride semiconductor single crystal while the crucible is rotated. In the growth of the semiconductor single crystal, the crucible having an inside diameter R (mm) is rotated at a maximum rotation speed &#x3c9; (rpm) satisfying the following conditions:&#x3c9;1&#x2212;4&#x2266;&#x3c9;&#x2266;&#x3c9;1+4;&#x3c9;1=10; andlog()+3.1.

Group III nitride semiconductor single crystal, method for producing the same, self-standing substrate, and semiconductor device

An object of the present invention is to realize, by the flux process, the production of a high-quality n-type semiconductor crystal having high concentration of electrons. The method of the invention for producing an n-type Group III nitride-based compound semiconductor by the flux process, the method including preparing a melt by melting at least a Group III element by use of a flux; supplying a nitrogen-containing gas to the melt; and growing an n-type Group III nitride-based compound semiconductor crystal on a seed crystal from the melt. In the method, carbon and germanium are dissolved in the melt, and germanium is incorporated as a donor into the semiconductor crystal, to thereby produce an n-type semiconductor crystal. The mole percentage of germanium to gallium in the melt is 0.05 mol % to 0.5 mol %, and the mole percentage of carbon to sodium is 0.1 mol % to 3.0 mol %.

N-type group III nitride-based compound semiconductor and production method therefor

In the production of GaN through the flux method, deposition of miscellaneous crystals on the nitrogen-face of a GaN self-standing substrate and waste of raw materials are prevented. Four arrangements of crucibles and a GaN self-standing substrate are exemplified. In FIG.A, a nitrogen-face of a self-standing substrate comes into close contact with a sloped flat inner wall of a crucible. In FIG.B, a nitrogen-face of a self-standing substrate comes into close contact with a horizontally facing flat inner wall of a crucible, and the substrate is fixed by means of a jig. In FIG.C, a jig is provided on a flat bottom of a crucible, and two GaN self-standing substrates are fixed by means of the jig so that the nitrogen-faces of the substrates come into close contact with each other. In FIG.D, a jig is provided on a flat bottom of a crucible, and a GaN self-standing substrate is fixed on the jig so that the nitrogen-face of the substrate is covered with the jig. A flux mixture of molten gallium and sodium is charged into each crucible, and a GaN single crystal is grown on a gallium-face under pressurized nitrogen.

Method for producing group III nitride-based compound semiconductor

An apparatus for manufacturing a Group III nitride semiconductor is composed of a pressure vessel, a reaction vessel disposed within the pressure vessel, a heating device disposed within the pressure vessel so as to heat the reaction vessel, and a glove box filled with argon gas. The pressure vessel and the glove box are connected to each other via a gate valve. By virtue of this configuration, a large-sized reusable reaction vessel can be disposed within the pressure vessel without causing oxidation of Na.

Apparatus for manufacturing group III nitride semiconductor

The invention provides a group III nitride semiconductor manufacturing system which is free from interruption to rotation of a rotational shaft. The group III nitride semiconductor manufacturing system has a reacting vessel having an opening, a crucible disposed in an interior of the reaction vessel and containing a melt including at least a group III metal and an alkali metal, a holding unit supporting the crucible and having a rotational shaft extending from the interior of the reaction vessel to an exterior of the reaction vessel through the opening, a rotational shaft cover covering a part of the rotational shaft positioned at the exterior of the reacting vessel and connected to the reacting vessel at the opening, a rotational driving unit disposed at an outside of the reacting vessel and regulating the rotational shaft and a supply pipe connected to the rotational shaft cover and supplying a gas including at least nitrogen into a gap between the rotational shaft and the rotational shaft cover, wherein the gas and the melt react to grow a group III nitride semiconductor crystal.

Group III nitride semiconductor manufacturing system

A GaN single crystalis grown on a crystal growth surface of a seed crystal (GaN layer) through the flux method in a nitrogen (N) atmosphere at 3.7 MPa and 870&#xb0; C. employing a flux mixture including Ga, Na, and Li at about 870&#xb0; C. Since the back surface of the templateis R-plane of the sapphire substrate, the templateis readily corroded or dissolved in the flux mixture from the back surface thereof. Therefore, the templateis gradually dissolved or corroded from the back surface thereof, resulting in separation from the semiconductor or dissolution in the flux. When the GaN single crystalis grown to a sufficient thickness, for example, about 500 &#x3bc;m or more, the temperature of the crucible is maintained at 850&#xb0; C. to 880&#xb0; C., whereby the entirety of the sapphire substrateis dissolved in the flux mixture.

Method for producing group III nitride-based compound semiconductor crystal

Objects of the invention are to further enhance crystallinity and crystallinity uniformity of a semiconductor crystal produced through the flux method, and to effectively enhance the production yield of the semiconductor crystal. The c-axis of a seed crystal including a GaN single-crystal layer is aligned in a horizontal direction (y-axis direction), one a-axis of the seed crystal is aligned in the vertical direction, and one m-axis is aligned in the x-axis direction. Thus, three contact points at which a supporting tool contacts the seed crystal are present on m-plane. The supporting tool has two supporting members, which extend in the vertical direction. One supporting member has an end part, which is inclined at 30&#xb0; with respect to the horizontal plane &#x3b1;. The reasons for supporting a seed crystal at m-plane thereof are that m-plane exhibits a crystal growth rate, which is lower than that of a-plane, and that desired crystal growth on c-plane is not inhibited. Actually, a plurality of seed crystals and supporting tools are periodically placed along the y-axis direction.

Method for producing a semiconductor crystal

In the flux method, a source nitrogen gas is sufficiently heated before feeding to an Na&#x2014;Ga mixture. The apparatus of the invention is provided for producing a group III nitride based compound semiconductor. The apparatus includes a reactor which maintains a group III metal and a metal differing from the group III metal in a molten state, a heating apparatus for heating the reactor, an outer vessel for accommodating the reactor and the heating apparatus, and a feed pipe for feeding a gas containing at least nitrogen from the outside of the outer vessel into the reactor. The feed pipe has a zone for being heated together with the reactor by means of the heating apparatus, wherein the zone is heated inside the outer vessel and outside the reactor.

Method and apparatus for producing group III nitride based compound semiconductor

Growing community of inventors

Aichi, Japan

Shiro Yamazaki