Gallium Carbide or Silicon Nitride: Which Is Best Material for Power Electronics Devices

As an alternative to silicon for power electronics evices, the main two options are without doubt silicon carbide and gallium nitride, the reason being the higher breakdown voltage that both of them have comparing to silicon.

Generally speaking, each one of two materials has its advantages and disadvantages: gallium nitride has a higher breakdown voltage when compared to silicon carbide, however, silicon carbide has a higher thermal conductivity and this property bodes well with applications that require high thermal dissipation       

The power electronics industry is divided in two camps, each one of them supporting the use of one or the other candidate material as replacement of silicon.

California, US-based Efficient Power Conversion is betting high on gallium nitride.

Believed to be the first company to actually having marketed MOSFETs based on gallium nitride, Efficient Power Conversion is now planning to move most of its offer about power electronics devices to GaN.

According to EPC`s co-founder Alex Lidow, gallium nitride is expected to reach price parity with silicon in a couple of years at latest and after that it is likely that silicon will mostly disappear from the power market.

Transphorm, another US-based company betting on gallium nitride, has recently reached an agreement with Fujitsu Inc. and Fujitsu Semiconductor to work together on gallium nitride- based devices by integrating their respective power device businesses.

International Rectifier, another company based in the US dealing with power electronic devices and formerly headed by the EFP co-founder Alex Lidow, has also adopted gallium nitride as their material of reference.

International Rectifier` s system and applications director Marco Palma explained this choice as follows: “We went directly to the best choice which is without any doubt gallium nitride. We are already serving some our major customers with GaN-based devices.

According to Mr. Palma, International Rectifier has been able to both raise the breakdown voltage of its inverters and make them more compact at the same time by moving away from silicon as material of reference.

Other companies all around the world are also betting high on gallium nitride.

But in the industry there is not a full consensus on gallium nitride as the best alternative to silicon for power electronics devices.

Anvil Semiconductors, a company based in the United Kingdom, is now working almost exclusively with silicon carbide. Silicon carbide, as discussed above, has the main advantage of having a higher thermal conductivity than gallium nitride and therefore SiC-based devices are more resistant to heat shocks and can be placed in positions where the heat would otherwise damage a device based on gallium nitride or silicon.

According to most researchers, in the medium to long-term future, it is likely that the two materials will coexist in the power electronics ecosystem and each one will be mostly used for particular applications: silicon carbide is likely to become most used in applications such as smart grids and high-speed trains while gallium nitride may become more popular with engine controlling systems in the automotive business (especially electric vehicles)

In other words, silicon carbide may become the solution of choice for devices requiring an amperage of less than 10KA to 50KA while gallium nitride may be used for applications that require higher amperages.

Author the Author -

This article is written by Matteo Martini, a nanotechnology expert based in Tokyo, Japan, specialized in: nanoimprint technology, patterned sapphire substrates for LED applications, sputtering, MEMS, GaN power devices and other related topics.