A substrate for single-crystal diamond laminated substrates and its manufacturing method, and a method for manufacturing single-crystal diamond substrates.

Abstract

This invention relates to a substrate for use as a single-crystal diamond laminate, comprising: an initial substrate containing at least one of amorphous carbon, glassy carbon, polycrystalline diamond, and single-crystal diamond with a linear expansion coefficient less than that of single-crystal α-Al₂O₃ and greater than 0.5 × 10⁻⁶ / K; a single-crystal α-Al₂O₃ layer on the initial substrate; and a heteroepitaxial layer composed of any one of iridium film, rhodium film, and platinum film on the single-crystal α-Al₂O₃ layer. This provides a substrate capable of forming a high-quality single-crystal diamond layer with a large area (large diameter) and high crystallinity, high purity, and low stress.

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