CVD diamond – a superior, multipurpose material for HF, high power density applications

March 15, 2018 // By Thomas Obeloer, Daniel Twitchen, Firooz Faili
Diamond possesses a remarkable set of properties, making it the ultimate solution for thermal management problems. Microwave-assisted undoped CVD (chemical vapor deposition) enables control of grain size, grain purity and grain interfaces to generate high-quality, high repeatability, polycrystalline diamond at the targeted thermal conductivity level needed for particular applications.

Commercially, CVD diamond, with fully isotropic characteristics is readily available in six different grades with thermal conductivities ranging from 700 to 2000 W/mK and bulk resistivity from 0.001 Ωm for doped diamond to 1012 Ωm for undoped diamond.

When facing heat flux from high power density hot spots in optoelectronics, RF power amplifiers or matching of high frequency loads through use of resistive terminations, CVD diamond delivers improved reliability and increased power handling. These step changes impact a wide range of disruptive electronics, from solid state RF PAs to advanced ASICs and laser diodes to 5G wireless and phased array radar.

Figure 1 shows a comparison of CVD diamond thermal conductivity and Table 1 is a representation of high frequency resistive advantages over other materials traditionally used for heat spreading and heat dissipation respectively.


Figure 1: Comparison of CVD diamond with ‘traditional’ heat spreading materials (Source: Element Six).


 Table 1: Capacitance per Watt table for resistive substrate (Source: Element Six).

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