Computer processors have shrunk to nanometer scales over the years, with billions of transistors sitting on a single computer chip. While the increased number of transistors helps make computers faster and more powerful, it also generates more hot spots in a highly condensed space. Without an efficient way to dissipate heat during operation, computer processors slow down and result in unreliable and inefficient computing. In addition, the highly concentrated heat and soaring temperatures on computer chips require extra energy to prevent processers from overheating.
An ultrahigh thermal-management material — defect-free boron arsenide — was developed that is more effective in drawing and dissipating heat than other known metal or semiconductor materials such as diamond and silicon carbide. The researchers integrated the material into computer chips with state-of-the-art, wide-band-gap transistors of gallium nitride called high-electron-mobility transistors (HEMTs).
When running the processors at near maximum capacity, chips that used boron arsenide as a heat spreader showed a maximum heat increase from room temperatures to nearly 188 °F. This is significantly lower than chips using diamond to spread heat, with temperatures rising to approximately 278 °F or the ones with silicon carbide showing a heat increase to about 332 °F.
These results clearly show that boron-arsenide devices can sustain much higher operation power than processors using traditional thermal management materials. Boron arsenide is ideal for heat management because it not only exhibits excellent thermal conductivity but also displays low heat transport resistance. When heat crosses a boundary from one material to another, there’s typically some slowdown to get into the next material. The boron arsenide material has very low thermal boundary resistance.
The team has also developed boron phosphide as another excellent heat-spreader candidate. During their experiments, the researchers first illustrated the way to build a semiconductor structure using boron arsenide and then integrated the material into a HEMT-chip design.