The Cold Hard Facts about Diamond Heat Spreaders

Diamond heat spreaders, also known as diamond thermal spreaders or diamond heat sinks, are passive components, made of synthetic diamond, that help dissipate potentially damaging heat generated in many electronic and photonic devices. Examples include high-power RF devices used in satellite communications, high-power laser diodes, high-power laser mirrors, and disk lasers.

A typical diamond heat spreader is a thin (up to 2 mm) sliver of synthetic diamond placed between the heat source and an actively or passively cooled heat sink. Good mechanical contact is essential; many applications utilize soldering or brazing, with mechanical clamping also occasionally used instead. These diamond heat spreaders offer several advantages over traditional thermal management materials like copper or aluminum, making them valuable in applications where efficient heat dissipation is critical.

While diamond is universally known for its hardness, there are actually two other properties - its electrical and thermal characteristics – that are key to diamond’s fast-growing use in heat spreaders.

Highest Thermal Conductivity. Diamond is an exceptional conductor of heat, with a thermal conductivity value of approximately 1,500-2,200 W/mK, depending on the product grade. This is significantly higher than that of other common materials like copper (up to 400 W/mK) and aluminum (up to 220 W/mK). This high thermal conductivity enables diamond to transfer heat away from heat sources more efficiently than any other material.

Best Electrical Insulator: If you want to draw heat from an electronic component and dissipate it in a metal heat sink, why use a diamond heat spreader as an extra interface layer rather than directly contacting? The main reason is that diamond is not only the best thermal conductor, it’s also a superb electrical insulator. It has similar electrical properties to glass and ceramics which have been widely used for electrical insulation for well over a century. So a diamond heat spreader is a prime candidate for any application where you need the highest possible heat flow and electrical isolation. That’s why so many of its applications involve high-power electronic or photonic components.

Diamond has several other advantages which can be important considerations in certain heat spreader applications.

Lightweight. Diamond heat spreaders are lightweight for two reasons. First, diamond is an inherently lightweight material. And second, because it’s such an effective insulator with extremely high breakdown properties, heat spreaders can be very thin. This is an advantage in satellite and other aerospace applications where overall system weight must be minimized.

Thermal Stability. Diamond has a low coefficient of thermal expansion, meaning it doesn't expand or contract significantly with changes in temperature. This characteristic helps maintain the integrity of devices like heat spreaders that are subject to thermal gradients. It also improves the long-term stability of these devices.

Corrosion Resistance. Diamond is highly resistant to chemical corrosion, including immunity to strong acids, bases, and even organic solvents. This makes diamond heat spreaders ideal for industrial and other applications where harsh environments may be encountered.

Exceptional Hardness. As most readers will already be aware, diamond is one of the hardest known materials, which is why synthetic diamond is widely used to coat saw blades and other edge tools for example. In the context of heat spreading, this toughness can be beneficial for applications where mechanical durability and abrasion resistance are required.

Optically Transparent. Diamond is optically transparent when created in an ultrapure form.

In a special high-temperature chamber, intense microwaves are used to create a plasma in carbon-containing methane gas. This releases free carbon atoms which deposit on a seed layer of diamond, slowly building up a wafer of polycrystalline CVD diamond.

Specific examples include high-performance CPUs and GPUs in computers and servers, especially in data center applications that require higher performance to support the growth of artificial intelligence (AI) and machine learning (ML) applications. They are also used in many LED lighting systems, particularly those involving high-intensity devices. Other applications of our diamond heat sinks include satellite and aerospace equipment, such as high-power radio frequency (RF) devices for satellite communications.

Using our world-class fabrication facility, we are able to create parts based on customer specifications with shapes as large as 145mm in diameter and thicknesses of up to 2mm and more that are ultra-flat and ultra-smooth to ensure optimum thermal contact to your device. Our diamond heat spreaders effectively distribute and dissipate heat away from heat-generating components, reducing the risk of overheating and prolonging the lifespan of electronic devices.