A method in which a carbonaceous protective film is formed on a rear surface of a single crystal SiC seed, the seed is placed in a reaction container without adhesion, and then single crystal SiC is grown from a SiC raw material on a front surface of the seed allows the seed to grow to a single crystal ingot having a large diameter since the absence of adhesion of the seed to a holder prevents the generation of warps or cracks attributed to a difference in thermal expansion coefficient between the seed and the holder during heating.

A sputtering target for a gallium nitride thin film, which has a low oxygen content, a high density and a low resistivity. A gallium nitride powder having powder physical properties of a low oxygen content and a high bulk density is used and hot pressing is conducted at high temperature in high vacuum to prepare a gallium nitride sintered body having a low oxygen content, a high density and a low resistivity.

The wafer having a retardation distribution measured with a light having a wavelength of 520 nm, wherein an average value of the retardation is 38 nm or less, wherein the wafer comprises a micropipe, and wherein a density of the micropipe is 1.5/cm.sup.2 or less, is disclosed.

Methods for making metastable lead-free piezoelectric materials are presented herein.

Methods for making metastable lead-free piezoelectric materials are presented herein.

Disclosed is a method for manufacturing a piezoelectric Al.sub.xGa.sub.1-xN (0.5≤x≤1) thin film, comprising: forming a stress control layer comprised of a Group III nitride on a silicon substrate by chemical vapor deposition (CVD); and depositing a piezoelectric Al.sub.xGa.sub.1-xN (0.5≤x≤1) thin film on the stress control layer, the thin film being deposited by PVD at 0.3 Tm (Tm is melting temperature of a piezoelectric thin film material) or higher. Further, a method for manufacturing a device in conjunction with piezoelectric Al.sub.xGa.sub.1-xN (0.5≤x≤1) thin films is provided.

A substrate for group-III nitride epitaxial growth and a method for producing the same is capable of fabricating a high-quality group III nitride single crystal at low cost. The substrate for group-III nitride epitaxial growth includes: a supporting substrate having a structure in which a core consisting of nitride ceramics is wrapped in an encapsulating layer having a thickness of between 0.05 μm and 1.5 μm, inclusive; a planarizing layer provided on an upper surface of the supporting substrate, the planarizing layer having a thickness of between 0.5 μm and 3.0 μm, inclusive; and a seed crystal layer consisting of a single crystal with a thickness of between 0.1 μm and 1.5 μm, inclusive, provided on an upper surface planarizing layer and having an uneven pattern on the surface.

A substrate for group-III nitride epitaxial growth and a method for producing the same is capable of fabricating a high-quality group III nitride single crystal at low cost. The substrate for group-III nitride epitaxial growth includes: a supporting substrate having a structure in which a core consisting of nitride ceramics is wrapped in an encapsulating layer having a thickness of between 0.05 μm and 1.5 μm, inclusive; a planarizing layer provided on an upper surface of the supporting substrate, the planarizing layer having a thickness of between 0.5 μm and 3.0 μm, inclusive; and a seed crystal layer consisting of a single crystal with a thickness of between 0.1 μm and 1.5 μm, inclusive, provided on an upper surface planarizing layer and having an uneven pattern on the surface.

Provided is a single crystal growth crucible including a first housing and a second housing, in which a fitting portion between the first housing and the second housing has a first protruding portion, which is provided by protruding inner wall side of the first housing toward the second housing, and a second protruding portion, which is provided by protruding outer wall side of the second housing toward the first housing and covers an outer circumferential surface of the first protruding portion, the first protruding portion is formed such that an outer diameter of a tip portion thereof is larger than that of a base portion thereof in the protruding direction, and the second protruding portion is formed such that an inner diameter of a tip portion thereof is smaller than that of a base portion thereof in the protruding direction, the outer diameter of the tip portion of the first protruding portion is equal to or smaller than the inner diameter of the tip portion of the second protruding portion at room temperature, and the outer diameter of the tip portion of the first protruding portion is larger than the inner diameter of the tip portion of the second protruding portion at a single crystal growth temperature.

Provided is a single crystal growth crucible including a first housing and a second housing, in which a fitting portion between the first housing and the second housing has a first protruding portion, which is provided by protruding inner wall side of the first housing toward the second housing, and a second protruding portion, which is provided by protruding outer wall side of the second housing toward the first housing and covers an outer circumferential surface of the first protruding portion, the first protruding portion is formed such that an outer diameter of a tip portion thereof is larger than that of a base portion thereof in the protruding direction, and the second protruding portion is formed such that an inner diameter of a tip portion thereof is smaller than that of a base portion thereof in the protruding direction, the outer diameter of the tip portion of the first protruding portion is equal to or smaller than the inner diameter of the tip portion of the second protruding portion at room temperature, and the outer diameter of the tip portion of the first protruding portion is larger than the inner diameter of the tip portion of the second protruding portion at a single crystal growth temperature.