CONNECTING THE COMPOUND SEMICONDUCTOR COMMUNITY
June 2012 Volume 18 Number 4
Editor-in-Chief David Ridsdale
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Editor Richard Stevenson PhD
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A more balanced view comes from the analysts. They expect both classes of device to have some success, with SiC being favoured at higher voltages, such as 600 V or more.
But there is another wide bandgap material that hardly anyone is talking about that has the potential to upset the applecart: Gallium oxide. This compound (Ga2
O3 ) has some great
attributes, including an incredibly wide bandgap of almost 5 eV that should unleash ultra-high efficiency devices with tremendous breakdown voltages.
One of the weaknesses afflicting the more established wide bandgap devices is the lack of an affordable, native substrate. To be cost-competitive, GaN devices must be grown on silicon. However, this requires the development of complex deposition processes to control stresses and strains associated with hetero-epitaxy. Such issues don’t plague SiC substrates, but prices are very high and unlikely to fall fast.
In stark contrast, if Ga2 Development of Ga2 O3
substrates were made in volume, their price would be very attractive. That’s because they can be made with the approach used for the manufacture of bulk sapphire.
O3 devices is in its infancy, with researchers from the National Institute of
Communications Technology in Japan leading the way (they tell their story in the feature “Gallium oxide trumps traditional wide bandgap semiconductors”, which starts on page 21 of this issue).
As you’d expect for any nascent technology, device performance is inferior to that associated with state-of-the-art SiC and GaN devices. But compared to their ancestors, Ga2
O3
their own in some areas, while excelling in others. If Ga2
O3 power electronics is to take off, researchers in this field will have to address several
issues. For example, there are currently no reports of hole conduction in p-type layers, and devices processing technologies must be developed alongside the production of substrates at least 4 inches in diameter. And once that’s done, products will have to be brought to market that can compete with the performance of next-generation GaN and SiC devices.
So success will be hard won, and could take many years to achieve. And in my view, while it’s certainly possible that Ga2
O3 2020.
Richard Stevenson Editor
will make a commercial impact, it will not happen until at least devices hold
sharon.cowley@
angelbc.com robin.halder@angelbc.com shehzad.munshi@
angelbc.com E:
tbrun@brunmedia.com E:
jjenkins@brunmedia.com
The perfect wide bandgap material When it comes to power devices, what is going to replace silicon as the dominant material?
That’s a tough question, and if you ask around you’ll get various answers. If you court the opinion of SiC diode and transistor manufacturers, you’ll be told that the future belongs to them. But that’s certainly not a view shared by the developers of GaN devices.
jackie.cannon@
angelbc.com david.ridsdale@angelbc.com
editorialview
June 2012
www.compoundsemiconductor.net 3
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