Application Scheme of Diamond Heat Sink in Wide Bandgap Semiconductor Power Modules

A heat sink is a passive heat dissipation component in the field of electronic devices, mainly serving as a heat absorber and radiator. It is usually made of materials such as metallic copper/aluminum, silicon carbide-aluminum, and diamond. Placed directly close to the heating surface, it transfers heat to the air, cooling liquid or additional radiators through heat exchange. Diamond material, featuring ultra-high thermal conductivity, high resistivity and low dielectric constant, is regarded as one of the most promising wide bandgap semiconductor materials.

Combining the above characteristics, the diamond heat sink, as a high thermal conductivity heat dissipation material with diamond as the core, has multiple superior properties such as high thermal conductivity, a thermal expansion coefficient matching that of semiconductor chips, and excellent insulation/dielectric performance. It is showing new vitality in the application of wide bandgap semiconductor power modules.

Application Scheme of Wide Bandgap Semiconductor Power Modules

(1) SiC Power Modules for New Energy Vehicles

With the increase in motor power density, the heat flux density of IGBT/SiC power modules has exceeded 500W/cm². By directly bonding the diamond heat sink to the back of the SiC power module, a direct "chip-diamond-radiator" heat transfer path is formed, which can directly conduct the hot spot heat of the vehicle inside the module and reduce the junction temperature by 20–35℃. Meanwhile, this method can effectively suppress the derating and out-of-control of devices caused by overheating, greatly improving the power density and safety of new energy vehicles.

Proposed copper-diamond composite embedded substrate for SiC power modules: (a) Physical image (b) X-ray image (c) Scanning electron microscope image of CDC

(Left) Simulated temperature distribution of power devices using diamond/Cu composite material; (Right) Simulated temperature distribution of power devices using conventional Cu heat sink

(Junction temperature variation of power devices with time for different heat dissipation materials)

(2) Industrial Inverter Modules

In industrial motor drive and frequency conversion systems, diamond heat sinks have become the preferred solution to overcome the heat dissipation bottleneck of high power density.

In the fields of rail transit and high-power motor drive, diamond heat sinks also improve the reliability and consistency of IGBT modules by virtue of their high thermal conductivity, so as to ensure the long-term stable operation of equipment under high load and improve the overall efficiency.