Ultra-high thermal-conductivity diamond and synthetic method therefor

Abstract

An ultra-high thermal-conductivity diamond is provided. The ultra-high thermal-conductivity diamond is polycrystalline diamond with a highly oriented crystals along <110> or <100> direction. It has a diameter of ≥100 mm in linear dimension and a thickness of ≥300 m, a thermal conductivity of ≥1800 W/(m·K) at 298K, and at least one surface with Ra≤10 nm, and further includes one or more of the following features: a content of nitrogen impurity ≤100 ppb, a dielectric constant ≥5.4 a dielectric loss tangent tanδ≤6×10, a volume resistivity ≥1×10Ωm, and a breakdown voltage ≥1000 V. The method for synthesizing the ultra-high thermal-conductivity diamond includes: providing a substrate for the diamond growth and a microwave plasma reactor, and performing the epitaxial growth of the ultra-high thermal-conductivity diamond on the substrate surface by using the reactor.