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High Thermal Conductivity in Boron Arsenide Bulk Crystals

Materials with high thermal conductivity can help to address a range of grand technological challenges, such as keeping nanoelectronic devices cool by removing the high-density heat generated within them. At room temperature, diamond and graphite, the two carbon allotrope bulk crystals, have a record high thermal conductivity of about 2000 W/m·K; however, high-quality natural diamond is scarce and expensive.

Although future technological advances may help to alleviate the cost of high-quality synthetic diamond, the large mismatch in the coefficient of thermal expansion between diamond and common semiconductors can introduce large thermal stresses. Common electronic materials such as copper and silicon have a thermal conductivity of about 400 and 150 W/m·K, respectively, which are well below the diamond value. The highest measured thermal conductivity values for semiconductors are about 490 W/m·K in silicon carbide and 460 W/m·K in boron phosphide.

Applications

  • Thermal transport in electronics, especially micro/nano-electronics
  • High thermal conductivity semiconductor

Problems Addressed

  • Development of the only known semiconductor with a bandgap comparable to silicon and an ultrahigh room-temperature thermal conductivity.
  • High-thermal-conductivity materials that may be more easily integrated into semiconducting devices.

Competitive Advantages

  • Demonstrated growth of BA bulk crystals from seed microparticles in a chemical vapor transport (CVT) process with thermal conductivity exceeding 1000 W/m·K.
  • This is twice the highest thermal conductivity of any previously demonstrated semiconductor, and approaching half that of diamond.
  • Capable of growing crystals 4 mm x 2 mm x 1 mm, almost 10x greater than previously reported sized crystals.

Patents

  • PCT Application Filed