Toyoda Gosei Co., Ltd.

Ngk Insulators, Inc.

Osaka University

Yasuhide Yakushi

Shiro Yamazaki

Seiji Nagai

Miki Moriyama

Takayuki Sato

Shohei Kumegawa

Yasuo Kitaoka

Katsuhiro Imai

Makoto Iwai

Koji Okuno

Yusuke Mori

Koichi Goshonoo

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

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 crystal and a GaN substrate, in which the transfer of dislocation density or the occurrence of cracks can be certainly reduced on a growth substrate, and the Group III nitride semiconductor crystal can be easily separated from a seed crystal. A mask layer is formed on a GaN substrate, to thereby form an exposed portion of the GaN substrate, and an unexposed portion of the GaN substrate. Through a flux method, a GaN layer is formed on the exposed portions of the GaN substrate in a molten mixture containing at least Group III metal and Na. At that time, non-crystal portions containing the components of the molten mixture are formed on the mask layer so as to be covered with the GaN layer grown on the GaN substrate and the mask layer.

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

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 mask layer is formed on a Ga polarity surface of the GaN substrate as a growth substrate. Subsequently, a protective film PF is formed on a N polarity surface of the GaN substrate. Then, a plurality of concave portions is formed from the mask layer extending to the GaN substrate, to thereby form a seed crystal. The seed crystal is etched in a Na melt, and a plurality of concave portions having a facet plane exposed. The seed crystal and the raw materials are placed in a crucible, and the pressure and temperature inside the crucible are increased. Thus, a target GaN layer is grown in the upward direction on the surface of the mask layer and the lateral direction over the concave portions.

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

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 %.

Growing community of inventors

Kiyosu, Japan

Yasuhide Yakushi