Manufacturing method for silicon carbide semiconductor substrates

Abstract

This invention provides a method for manufacturing a SiC semiconductor substrate that can be used with a general-purpose ion implantation apparatus that does not require a neutron shielding structure. [Solution] After preparing a single-crystal SiC substrate 3, oxygen is injected from one side 3a of the single-crystal SiC substrate to form an oxygen-injected layer 4 at a predetermined depth from the side 3a. Alternatively, after preparing a polycrystalline SiC substrate 1, one side 1a of the polycrystalline SiC substrate 1 is joined to one side 3a of the single-crystal SiC substrate 3 to form a bonded substrate 6. Then, by heat treatment, the oxygen contained in the oxygen-injected layer 4 reacts with the carbon or silicon contained in the single-crystal SiC substrate 3, thereby peeling off the single-crystal SiC substrate 3 at the location of the oxygen-injected layer 4 and forming a structure in which a single-crystal SiC layer 2, composed of a part of the single-crystal SiC substrate 3, is provided on the polycrystalline SiC substrate 1.

Claims

1. Prepare a single-crystal silicon carbide substrate (3), Oxygen is injected from one side (3a) of the single-crystal silicon carbide substrate to form an oxygen-injected layer (4) at a predetermined depth from that side, Prepare a polycrystalline SiC substrate (1), A bonded substrate (6) is formed by bonding one surface (1a) of the polycrystalline silicon carbide substrate to one surface of the single-crystal silicon carbide substrate, By heat treatment, the oxygen contained in the oxygen-injected layer reacts with the carbon or silicon contained in the single-crystal silicon carbide substrate, thereby peeling off the single-crystal silicon carbide substrate at the location of the oxygen-injected layer, and forming a structure on the polycrystalline silicon carbide substrate in which a single-crystal silicon carbide layer (2), composed of a part of the single-crystal silicon carbide substrate, is provided. A method for manufacturing a silicon carbide semiconductor substrate containing [the specified material].

2. A method for manufacturing a silicon carbide semiconductor substrate according to claim 1, wherein the temperature of the heat treatment is 700°C or higher and 2500°C or lower.

3. A method for manufacturing a silicon carbide semiconductor substrate according to claim 2, wherein the temperature of the heat treatment is 1800°C or higher.

4. A method for manufacturing a silicon carbide semiconductor substrate according to claim 2, wherein the temperature of the heat treatment is 2300°C or lower.

5. A method for manufacturing a single-crystal silicon carbide substrate according to claim 1, comprising introducing an element of nitrogen, phosphorus, boron, or aluminum, which serves as an ion for reducing interfacial resistance at the bonding interface, to at least one of the one surface of the single-crystal silicon carbide substrate and the one surface of the polycrystalline silicon carbide substrate before forming the bonding substrate.

6. A method for manufacturing a single-crystal silicon carbide substrate according to any one of claims 1 to 5, wherein the bonding substrate is formed by irradiating one surface of the single-crystal silicon carbide substrate and one surface of the polycrystalline silicon carbide substrate with an argon beam in a vacuum to expose dangling bonds, and bonding the dangling bonds of the one surface of the single-crystal silicon carbide substrate and the one surface of the polycrystalline silicon carbide substrate together.

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