Nano Materials International has introduced aluminum diamond metal matrix composites (MMC) for use as heat spreaders that can reduce GaN junction temperatures by up to 25 percent, has a coefficient of thermal expansion (CTE) close to that of SiC and metallization well suited for die attach. They also have excellent dimensional tolerances and material stability. In addition, they can be economically produced in large quantities while adding a minimal cost to each GaN device.
Polycrystalline diamond has the highest thermal conductivity of any material, ranging from 1200 to 2000 W/mK. When used in an aluminum diamond MMC, the effective conductivity remains over 500 W/mK, far higher than common heat spreader materials such as copper tungsten (200 W/mK), copper molybdenum (250 W/mK) and copper-molybdenum-copper (350 W/mK). The MMC material with nickel-gold electrolytic or electroless plating can be made in the thicknesses required for use as a heat spreader and in virtually any shape and size typical of GaN HEMT or MMIC devices. It is available as a MMC material alone or incorporated within a package, allowing it to accommodate the specific needs of device manufacturers and package suppliers.
The aluminum diamond MMC products have been tested with a variety of GaN devices and are proving well suited for solving the problems created by GaN's extremely high power density. They are likely to be an essential part of the solution for removing heat at the device level from high power RF and microwave amplifiers that will be employed in future generations of military electronic warfare, radar, and communications systems.
Nano Materials International