Shin-Etsu Chemical Co., Ltd.

Norio Yamagata

Takehisa Minowa

Naofumi Shinya

Yu Hamaguchi

Tadao Nomura

Toshihiro Tsumori

Osamu Yamada

A SiC single crystal is produced by impregnating a molten alloy of silicon and a metallic element M that increases carbon solubility into a SiC sintered body to form a SiC crucible, placing silicon and M in the crucible and heating the crucible to melt the silicon and M and form a Si—C solution, dissolving silicon and carbon in the solution from surfaces of the crucible in contact with the solution, contacting a SiC seed crystal with the top of the solution to grow a first SiC single crystal on the SiC seed crystal by a solution process, and bulk growing a second SiC single crystal on a face of the solution-grown first SiC single crystal by a sublimation or gas process. This method enables a low-dislocation, high-quality SiC single crystal to be produced by a vapor phase process.

Method for producing SiC single crystal and method for suppressing dislocations in SiC single crystal

In the present invention, in producing a SiC single crystal in accordance with a solution method, a crucible containing SiC as a main component and having an oxygen content of 100 ppm or less is used as the crucible to be used as a container for a Si&#x2014;C solution. In another embodiment, a sintered body containing SiC as a main component and having an oxygen content of 100 ppm or less is placed in the crucible to be used as a container for a Si&#x2014;C solution. The SiC crucible and SiC sintered body are obtained by molding and baking a SiC raw-material powder having an oxygen content of 2000 ppm or less. SiC, which is the main component of these, serves as a source for Si and C and allows Si and C to elute into the Si&#x2014;C solution by heating.

SiC crucible, SiC sintered body, and method of producing SiC single crystal

A SiC single crystal is prepared by the solution process of placing a seed crystal in contact with a Si&#x2014;C solution in a crucible and letting a SiC single crystal to grow from the seed crystal. The method includes the first growth step of conducting crystal growth using (0001) or (000-1) plane of a SiC single crystal of which the seed crystal is composed, as the growth surface, and the second growth step of conducting crystal growth using (1-100) or (11-20) plane of a SiC single crystal resulting from the first growth step as the growth surface. A SiC single crystal of high homogeneity and quality is obtained, which is reduced in threading screw dislocations, threading edge dislocations, basal plane dislocations, micropipes, and stacking faults.

Method for preparing SiC single crystal

A method of producing a SiC single crystal includes: disposing a SiC seed crystal at a bottom part inside a graphite crucible; causing a solution containing Si, C and R (R is at least one selected from the rare earth elements inclusive of Sc and Y) or X (X is at least one selected from the group consisting of Al, Ge, Sn, and transition metals exclusive of Sc and Y) to be present in the crucible; supercooling the solution so as to cause the SiC single crystal to grow on the seed crystal; and adding powdery or granular Si and/or SiC raw material to the solution from above the graphite crucible while keeping the growth of the SiC single crystal.

Method of producing SiC single crystal

In the present invention, a crucible formed of SiC as a main component is used as a container for a Si&#x2014;C solution. A metal element M (M is at least one metal element selected from at least one of a first group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Lu, a second group consisting of Ti, V, Cr, Mn, Fe, Co, Ni and Cu and a third group consisting of Al, Ga, Ge, Sn, Pb and Zn) is added to the Si&#x2014;C solution and the crucible is heated to elute Si and C, which are derived from a main component SiC of the crucible, from a high-temperature surface region of the crucible in contact with the Si&#x2014;C solution, into the Si&#x2014;C solution. In this way, precipitation of a SiC polycrystal on a surface of the crucible in contact with the Si&#x2014;C solution is suppressed.

Method for growing silicon carbide crystal

In the present invention, a crucible formed of SiC as a main component is used as a container for a Si&#x2014;C solution. The SiC crucible is heated such that, for example, an isothermal line representing a temperature distribution within the crucible draws an inverted convex shape; and Si and C, which are derived from a main component SiC of the crucible, are eluted from a high-temperature surface region of the crucible in contact with the Si&#x2014;C solution, into the Si&#x2014;C solution, thereby suppressing precipitation of a SiC polycrystal on a surface of the crucible in contact with the Si&#x2014;C solution. To the Si&#x2014;C solution of this state, a SiC seed crystal is moved down from the upper portion of the crucible closer to the Si&#x2014;C solution and brought into contact with the Si&#x2014;C solution to grow a SiC single crystal on the SiC seed crystal.

Provided is a surface-treated substrate in which the roughness of the surface of the substrate is controlled. The surface-treated substrate can form a magnetic recording medium in which head flying stability is maintained and which has a magnetic film that can achieve high recording densities. Also provided is a method for roughening the surface of the substrate. More specifically, provided is a surface-treated silicon substrate for a magnetic recording medium in which a surface used for forming a recording layer has 40 to 1000 protrusions per 1 &#x3bc;mwith a maximum height of 10 nm or less and an average roughness of 0.3 to 2.0 nm, and in which there are no defects or spots on any of the surface. Furthermore, provided is a method for manufacturing the surface-treated silicon substrate for the magnetic recording medium, comprising a step of etching a surface of a silicon substrate, wherein ultrasound is applied to the surface of the silicon substrate with the substrate shaken or rotated. Also provided is a magnetic recording medium, comprising the silicon substrate.

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Fukui, Japan

Norio Yamagata