Bohr Materials

Polycrystalline Heat Spreader Plates

A round polycrystalline diamond plate in a tray, held in gloved hands.

Polycrystalline CVD plates that pull heat out of high-power devices, in wafer sizes to 150 mm.

Polycrystalline CVD diamond carries more than 1000 W·m⁻¹·K⁻¹ at 300 K while expanding at only 1.0 ppm·K⁻¹ and insulating electrically. That combination is what lets a spreader sit directly under a device without shorting it or straining the die.

Plates are finished to a drawing: diameter, thickness and surface roughness are set per order.

  • Ultra-high thermal conductivity
  • Low thermal expansion coefficient
  • Excellent electrical insulation
  • Chemical stability and mechanical strength
  • Polycrystalline gives the larger size capability; single-crystal gives the higher thermal conductivity

Specifications

Thermal conductivity at 300 K> 1000 W·m⁻¹·K⁻¹
Thermal diffusivity at 300 K> 800 mm²·s⁻¹
Thermal expansion coefficient at 300 K1.0 ± 0.1 ppm·K⁻¹
Specific heat capacity at 300 K0.502 J·g⁻¹·K⁻¹
Hardness81 ± 18 GPa
Young's modulus1050 GPa
Poisson's ratio0.1
Density3.52 g·cm⁻³
Resistivity1.0×10¹² – 1.0×10¹³ Ω·m
Surface roughness Ra< 5 nm
Reference sizes25, 50, 75, 100, 125, 150 mm diameter (customisable)
Thickness< 1.0 mm (customisable)

Reference values from the producer datasheet. Dimensions marked customisable are set per order. Request a quote to have a specification confirmed against your drawing.

Applications

Heat spreader plates go wherever the heat flux has outrun copper and the spreader has to stay electrically isolating.

  • High-power semiconductor devices, including EV traction power modules
  • Optoelectronics: high-power LED lighting and solid-state lasers
  • Quantum technology: quantum chips and quantum sensors
  • Aerospace

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