CVD Diamond:
Thermal Properties

Thermal Conductivity

One of many remarkable properties of diamond is its uncompeted thermal conductivity. In contrast to metals, where conduction electrons are responsible for the high thermal conductivity, heat is conducted in electrical insulators by lattice vibrations. With a sound velocity of 17500 m/s, diamond is the material with the highest Debye temperature (2220 K), exceeding that of most other insulating materials by an order of magnitude and leading to the highest thermal conductivity of any
material at room temperature (20-25W/cmK), exceeding that of copper by a factor of five. 

Thermal conductivity of CVD diamond vs. temperature. For comparison, the thermal conductivity of copper is shown in red. 

Large area CVD diamond films have been proposed for many thermal management applications, though the first thermal conductivity measurements in the late 80’s were not very promising. In recent years, however, the quality of CVD diamond improved dramatically, and large area CVD diamond plates with thermal conductivities around 20 W/cmK became available. Today, CVD diamond is used for various thermal management applications such as submounts for integrated circuits and heat spreaders for high power laser diodes.

Mapping of the thermal conductivity