Diamond Heat Sink: The Key Material to Break Through the Thermal Dissipation Bottleneck of High-Power Radar

With the rapid development of autonomous driving technology, radar, as a core sensor, plays an irreplaceable role in environmental perception. However, radar generates substantial heat during operation, with laser transmitters accounting for 40%-60% of total heat dissipation and data processing units (DPUs) contributing 20%-30%. Traditional thermal management materials are no longer capable of meeting the high-power-density heat dissipation requirements. Thanks to its exceptional thermal conductivity, diamond heat spreaders have emerged as the key material to address the thermal challenges of autonomous driving radars, providing reliable support for the stable operation of autonomous driving systems.

The thermal conductivity of diamond heat spreaders can reach 2000-2200 W/(m·K) at room temperature. This ultra-high thermal conductivity enables rapid transfer of heat generated by electronic devices, effectively reducing the junction temperature of chips. Diamond also boasts an ultra-high resistivity of up to 10^16 Ω·cm, classifying it as a typical electrical insulator that eliminates the risk of short circuits. Its coefficient of thermal expansion (CTE) is highly compatible with silicon and silicon carbide—the core materials of semiconductor chips (2.7×10^-6/K). This close thermal matching ensures that diamond heat spreaders maintain stable interfaces even after undergoing over ten thousand temperature cycles, effectively preventing interface delamination caused by CTE mismatch and significantly enhancing device reliability and service life. Additionally, diamond retains stable performance across an extreme temperature range (-200°C to 1000°C), making it suitable for complex battlefield environments. It exhibits excellent corrosion resistance to acids, alkalis, and organic solvents at room temperature and maintains stability even at high temperatures. Furthermore, diamond possesses exceptional mechanical strength, with a Vickers hardness of 8000-10000 kg/mm² and a fracture strength of 350 MPa, rendering it ideal for high-stress applications.

Diamond heat spreaders can be directly used as heat dissipation substrates for laser transmitters. By making direct contact with the active region of lasers, they leverage diamond’s ultra-high thermal conductivity to uniformly distribute heat across the substrate. At the interface between laser transmitters (VCSEL/EEL) and heat dissipation structures, diamond heat spreaders achieve extremely low contact thermal resistance, ranging from 0.05-0.08 °C·cm²/W—representing over 50% higher thermal conduction efficiency compared to silicone pads of the same thickness (0.15-0.2 °C·cm²/W). Their phase transition temperature is engineered to 45-55°C, slightly below the maximum operating temperature of VCSELs. During chip operation, diamond heat spreaders liquefy to fill gaps; at room temperature, they remain solid, eliminating contamination risks to adjacent optical components. Moreover, they require no press-fit fixation, thus preventing chip damage caused by mechanical stress.

At the interface between data processing units (FPGA/ASIC) and heat sinks, diamond heat spreaders transform into a gel-like state after phase transition, offering a degree of elasticity that compensates for stress variations induced by screw fixation, thereby avoiding contact thermal resistance degradation over long-term use. Certain diamond heat spreader variants incorporate reinforcing fillers (e.g., graphite microplates), achieving thermal conductivity levels of 8-15 W/(m·K)—comparable to high-thermal-conductivity thermal greases (10-20 W/(m·K)). Unlike greases, however, they require no manual application, enabling higher assembly efficiency and making them well-suited for mass production.

Diamond microchannel heat sinks utilize diamond film materials with a thermal conductivity of up to 2000 W/(m·K). Through the design of high-efficiency microchannel structures and an architecture featuring direct bonding to power chips combined with thermal spreading, they can meet the heat dissipation demands of power components with heat flux densities exceeding 1 kW/cm². Femtosecond laser processing technology for diamond microchannels has realized a positive correlation between microgroove depth and laser power/scan count, as well as a negative correlation with scan speed. Under optimized parameters, the fabricated diamond microgrooves exhibit regular structural shapes, with the taper of cross-sectional sidewalls controlled within 3°, and free of surface defects such as residues, cracks, and edge chipping.

With their ultra-high thermal conductivity, superior thermal performance compatibility, and wide-temperature stability, diamond heat spreaders have established themselves as the ideal material for solving the thermal management challenges of autonomous driving radars. By directly contacting the active regions of lasers and data processing units, they significantly reduce chip junction temperatures, enhancing laser power stability and system reliability. Looking ahead, driven by the explosive growth of AI, 5G, new energy vehicles, and military applications, the diamond heat spreader market is poised to experience a hundredfold growth in the next 5-10 years, providing robust support for the safety and intelligence of autonomous driving technology.

CSMH uses the MPCVD method to prepare large-sized and high-quality diamonds,and currently has mature products such as diamond heat sinks, diamond wafers, diamond windows,diamond composite materials,etc.Among them,the thermal conductivity of diamond heat sinks is 1000-2200w/（m.k）, which has been applied in aerospace, high-power semiconductor lasers, optical communication, chip heat dissipation, nuclear fusion and other fields.