GaN community grows: ex-IR CEO launches GaN-based power transistors

Hot on the heels of International Rectifier’s announcement last month of its first Gallium Nitride (GaN) -on-Silicon product comes an announcement by start-up company Efficient Power Conversion Corp. (EPC) of its new family of power transistors based on its proprietary GaN-on silicon technology. The transistors’ V_ds ranges from 40V to 200V and R_ds(on) from 4 to 100m§Ù. The company claims that GaN devices can reduce total server power requirements – including ac-dc and dc-dc losses and fans – by about 18%.

The enhancement mode –normally OFF– GaN technology was explicitly developed to replace power MOSFETs. Says Alex Lidow, EPC’s co-founder and CEO, enhancement mode — rather than depletion mode – is essential for GaN to become a broad-scale silicon power MOSFET replacement. “It’s meant to imitate the functionality of a power MOSFET on supersteroids.” Because the GaN structures can be laid down on a standard 6 in.wafer, the price is comparable to high-end MOSFETS: $0.80 and $5.00 in 1k quantities. (You can buy them today at Digikey.)

R_ds(on) for a given device area is a key determinant of cost, and the equivalent Gan transistor is markedly smaller than the equivalent MOSFET as you can see below.

Note that the MOSFET is shown packaged, while the GaN device is a bare die. This is a valid size comparison because since the GaN structure is laid down on a silicon layer that acts as an insulator and the device is hermetically sealed so it requires no package. The GaN transistor can be mounted directly on a heat sink with no surrounding packaging and no thermal resistance between the transistor and its package.

Here are more specs:

How does this new family compare with IR’s iP2010 and iP2011? First off, IR’s devices are native depletion mode – although according to Dr. Mike Briere, responding to a question posed during an IR seminar at APEC, they can be made in enhancement mode. In addition, the EPC transistors are just that – discrete transistors, while IR’s product is a integrated power stage devices that integrates a driver IC matched to a multi-switch GaN transistor, all mounted in a flip chip package.

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The Rest of the Story: What about the fact that Alex Lidow of EPC was, until October 2007, the CEO of International Rectifier? Lidow has stated that all of EPD’s intellectual property was developed and owned entirely by them, However, IR filed suit late last year against Lidow, claiming theft of trade secrets. From a PowerPulse article in January:

“IR claims that Lidow stalled IR from making its GaN technology public in 2007, and instead began secretly recruiting the above referenced IR staff (from the R&D team plus senior sales representatives) for his plan to establish a new firm – EPCC, supposedly to provide rival GaN-based products.

Legal representation for Lidow and EPCC claim that the defendants are not using IR’s GaN technology, and that EPCC is developing a different semiconductor product.”