Silicon carbide substrate having excellent flatness and low basal plane dislocation density
AssigneeProterial, Ltd.
InventorsSadahiko Kondo, Junya Ikeda
Life of this patent
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Abstract
A new substrate manufacturing method of obtaining a SiC epitaxial substrate having excellent flatness and a SiC epitaxial substrate having excellent flatness are provided. In a Sic epitaxial substrate having an epitaxial film obtained by epitaxially growing silicon carbide on a front surface of a silicon carbide substrate, the SiC epitaxial substrate has a first main surface made of the epitaxial film and a second main surface opposite to the first main surface. A maximum value of SBIR on the second main surface based on a 10 mm square site satisfies a condition of 0.1 μm or more and 1.5 μm or less.
Claims8
A SiC epitaxial substrate having an epitaxial film obtained by epitaxially growing silicon carbide on a front surface of a silicon carbide substrate,
- wherein the SiC epitaxial substrate has a first main surface made of the epitaxial film and a second main surface opposite to the first main surface, and has a diameter of 150 mm or more, and
- a maximum value of SBIR on the second main surface based on a 10 mm square site is 0.1 μm or more and 1.5 μm or less, and a maximum value of SFQR on the first main surface based on the 10 mm square site is 0.1 μm or more and 1.5 μm or less;
- wherein, the epitaxial film includes a buffer layer and a drift layer, the buffer layer being made of two or more layers comprising a low-concentration layer and a hole barrier layer, and the epitaxial film includes a layer having an impurity concentration of 5×1018 cm−3 or more and 1×1019 cm−3 or less, wherein the basal plane dislocation density of the surface of the epitaxial film is 0.01 cm−2 or less.
A method of manufacturing a SiC epitaxial substrate comprising steps of:
- (a) preparing a plate-shaped silicon carbide substrate;
- (b) forming a first main surface made of an epitaxial film by epitaxially growing silicon carbide on a front surface of the silicon carbide substrate;
- (c) forming a protective film on a surface of the epitaxial film;
- (d) forming a second main surface by grinding or polishing a surface of the silicon carbide substrate, the surface being opposite to the first main surface, based on a shape of the first main surface;
- and
- (e) removing the protective film;
- wherein, the protective film is made of a resist,
- wherein the resist is a positive-tone resist containing at least one type material selected from ethyl lactate and butyl acetate.
Dependencies are inferred from the claim text.