Substrate for recording medium, and magnetic recording medium using same
View Patent ↗A substrate for a recording medium suited for thermally assisted recording methods has a disc shape with a center hole and includes a silicon single-crystal supporting member; an SiO 2 film formed on the silicon single-crystal supporting member; a main face having a film thickness of the SiO 2 film thereon which is less than 10 nm; a substrate inner periphery end face adjacent to the center hole; a substrate inner periphery chamfer portion adjacent to the main face and to the substrate inner periphery end face; a substrate outer periphery end face positioned on the side of the main face opposite the substrate inner periphery end face; and a substrate outer periphery chamfer portion adjacent to the main face and to the substrate outer periphery end face. A magnetic recording medium includes at least the above substrate and a magnetic recording layer formed on the substrate.
1. A magnetic recording medium that has a disc shape with a center hole, comprising:
a silicon single-crystal supporting member having
a main face,
a substrate inner periphery end face adjacent to the center hole,
a substrate inner periphery chamfer portion adjacent to the main face and to the substrate inner periphery end face,
a substrate outer periphery end face positioned on a side of the main face opposite the substrate inner periphery end face, and
a substrate outer periphery chamfer portion adjacent to the main face and to the substrate outer periphery end face;
an SiO 2 film formed on the silicon single-crystal supporting member; and
a magnetic recording layer formed on the supporting member for the magnetic recording medium;
wherein
a thickness of the SiO 2 film on the main face ranges from 2 nm to 8 nm, and
a thickness of the SiO 2 film on the substrate inner periphery end face and the substrate inner periphery chamfer portion ranges from 50 nm to 200 nm.
2. The magnetic recording medium according to claim 1 , wherein the SiO 2 film on the substrate outer periphery end face has a film thickness of 10 nm or less.
3. The magnetic recording medium according to claim 2 , wherein at least the SiO 2 film on the substrate inner periphery end face and the substrate inner periphery chamfer portion is formed by thermal oxidation of the silicon single-crystal supporting member.