WHY DiAMOND?

Diamond is a unique material for electronic and electron device applications.Take a look at any comparative table of physical properties and the reasons are obvious (and why exponents of competing materials such as gallium nitride and silicon carbide always omit the diamond column from their presentations!):

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Where diamond really scores is its unique dual ability to insulate very high voltages across very thin layers of the material and at the same time conduct heat 5 times better than copper.

The lower the insulation strength, the more base material you need to start with. This is a big issue for wide bandgap materials, which are at least 10 times more expensive than silicon to produce. More importantly, the more semiconductor material the slower the device operates. This is why, in the case of power semiconductors, 6,500V appears to be the ultimate practical limit for silicon insulated gate bipolar transistors (IGBTs).

Likewise heat, and the ability to remove it from the active region within an electronic device is critical to ultimate operating performance. Diamond's ability to almost instantaneously conduct heat away from the active region, means it can deliver higher performance from a given size of device.

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If you continue to explore further, look at the benchmark factors that have been proposed to compare various wide bandgap semiconductors for their suitability for power electronic or high frequency applications and the disparity becomes even more apparent. All these benchmarks are based on the constants relating to the material properties listed above as they are applied in the engineering formulae that underpin the design of semiconductor devices:

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Despite its obvious intrinsic advantages, diamond has struggled in the past to make any significant progress as a semiconductor material. The reason for this is because of two widely held perceptions:

Historically there has been limited availability of high-quality substrate materials

Over the past 10 years there have been major advances in the production of synthetic-diamond by Chemical Vapour Deposition. Today there are several leading material growers offering extremely high-quality diamond materials in single crystal, polycrystal (µm grain size) and nano-crystalline (5nm to 100nm grain size) forms, with wafer sizes up to 200mm available in the non-single crystal forms and 25mm in single-crystal form. These multiple forms of diamond offer a choice of characteristics that mean the most appropriate form can be selected for any given application. Further, and more importantly, the scaled production cost of diamond is projected to be on a par with all other major wide-band-gap materials in use today.

Inability to dope diamond in the same way as silicon (in particular n-type) means that it's not possible to make practical electronic devices

This misconception has dogged diamond for decades. While it is highly unlikely that a truly effective compatible n-type dopant will be found for diamond, there is also an unspoken truth about diamond: it's not a semiconductor, rather it's an electrical insulator with some phenomenal charge transport properties. Making good working devices in diamond first requires tearing up the rule book to fully exploit its unique properties.

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