Lidow returns with 'disruptive' GaN startup
Mark LaPedus
EE Times

03/08/2010 12:01 AM EST
URL: http://www.eetimessupplynetwork.com/223200049

SAN JOSE, Calif. -- A startup led by chip veteran Alex Lidow has officially announced its formation, disclosed its supply-chain partners and unveiled its first products in the emerging gallium nitride (GaN) arena.

The startup, Efficient Power Conversion Corp. (EPC), is not going after the traditional market for GaN, which is the radio-frequency (RF) sector. Instead, using a GaN-on-silicon technology, EPC (El Segundo, Calif.) is launching a line of GaN transistors for power management applications, a market dominated by traditional power MOSFETs over the last several decades.

EPC is looking to take share--or dethrone--the power MOSFET in applications like audio systems, LCD TVs, notebooks, servers and other products. EPC claims to have developed a proprietary enhancement-mode GaN transistor technology that will ultimately replace power MOSFETs. In total, the GaN transistor market is expected to hit $264 million by 2013, according to iSuppli Corp.

Ironically, EPC will go toe-to-toe with Lidow's former firm--International Rectifier Corp. (IR)--which recently rolled out a competitive GaN line. But it is unlikely that the power MOSFET suppliers--such as Fairchild, Infineon, IR, TI, Vishay and others--will throw in the towel and give the market away to EPC.

Still, both EPC and IR believe that today's power MOSFETs are hitting the performance wall, thereby propelling the need for a new technology.

"EPC's GaN-on-silicon power transistors represent the first major breakthrough in power conversion technology since the development of the commercial power MOSFET. We have developed a very cost effective and reliable technology that is also very easy for anyone with power MOSFET experience to use in a way that will significantly boost their power management system performance" said Lidow, EPC's co-founder and chief executive.

''In the same way that power MOSFETs displaced the bipolar transistor in the 1980s, GaN transistors will displace power MOSFETs in the coming years,'' said Lidow, who was the former CEO of IR.

There are other dynamics in play as well. According to IMS Research, Cree Inc. will roll out what appears to be a rival MOSFET based on silicon carbide (SiC). There are GaN-based power devices coming from EPC, Fujitsu, IR and others, while several other companies are pursuing the release of GaN Schottky diodes, according to IMS.

The SiC and GaN power device market will be worth over $160 million by 2013, said Josh Flood, an analyst at IMS Research. "The next three years will be an important stage in the development of the SiC and GaN power device market,'' he said. ''Applications other than PFC power supplies are forecast to begin to adopt these new power devices and other established power semiconductor suppliers have indicated they will be introducing new SiC and GaN power devices to the market in the near future."

Power MOSFETs are basically metal-oxide semiconductor field-effect transistors. For years, power MOSFETs have been used to handle large amounts of power at high speeds and efficiencies with low voltages.

Meanwhile, there has been a lot of hype about GaN over the years, but the technology has failed to live up to its promises. GaN is a material that has attractive wide bandgap characteristics; it tolerates higher voltages than conventional silicon and gallium arsenide (GaAs).

GaN has moved into production as a critical material for LEDs. The bandgap characteristics of GaN also make it attractive for RF, but the technology has been difficult to make in volumes until recent times. Several companies, including Cree, Eudyna, RFMD, and Nitronex, are targeting GaN for LED and RF applications.

Now, the technology could have a new application in power management. For example, today's power supplies take AC power from a wall outlet and convert it to DC. A power supply uses silicon transistors, which, in many cases, suffers from some power loss. One-third of all losses can be attributed to the silicon transistor.

''Power management is a large and growing market that is constantly in need of higher energy efficiency,'' Lidow said. ''Silicon has reached performance limits in power management. Gallium nitride enables a game-changing price/performance ratio.''

Based on the family pedigree, EPC is a company to watch. Lidow's father, Eric Lidow, and his grandfather, Leon Lidow, founded International Rectifier in 1947. Alex Lidow himself joined IR in 1977. A co-inventor of the HEXFET power MOSFET, Alex Lidow was elected a director and CEO of IR in 1995. He resigned from the position of CEO in October of 2007 after accounting irregularities had been discovered at IR.

Alex Lidow, and EPC, suddenly surfaced in January of 2010, when IR (El Segundo, Calif.) sued its former CEO. According to court documents, Alex Lidow was (and still is) affiliated with Efficient Power Conversion. The court case alleges Alex Lidow stole intellectual property related to GaN power devices. Lidow and his company deny the charges, according to reports.

At about the same time as the suit, IR announced it had started making prototype devices using a proprietary GaN-based power device technology platform. IR's first GaN products, the iP2010 and iP2011, are power stage devices designed for multiphase and point-of-load (POL) applications, including servers, routers, switches and general purpose POL DC-DC converters.

IR's technology, dubbed GaNpowIR, is based on the company's 150-mm GaN-on-silicon epitaxial technology. The technology is based on a depletion-mode GaN HEMT structure, which can be fabricated using standard CMOS production tools.

For years, the industry has been looking at GaN for power management to replace the power MOSFET. The problem is that ''GaN does not always want to grow on silicon,'' said Tim McDonald, vice president of emerging technologies at IR.

This is mainly due to the ''mismatch with the lattice'' with GaN; in additional, there are issues with the thermal co-efficiency of expansion with GaN, he said. However, IR said it solved the nagging problems with its technology, thereby enabling GaN to move into the power management space.

Like Lidow, McDonald also believes that GaN will eventually replace silicon-based power MOSFETs. "I think silicon MOSFETs will be around for several years,'' he said. ''But is silicon running out of gas? Yes. GaN will ultimately replace or displace power MOSFETs between 20 Volt to 1,200 Volt applications.''

Claiming it has ''disruptive'' technology, startup EPC is taking another approach to the problem. Formed in 2007, the company was founded by Alex Lidow and other employees from IR. The privately-held fabless company received undisclosed funding from Taiwan's Episil, which also happens to be EPC's foundry partner.

EPC has also formed partnerships with Advanced Semiconductor Engineering Inc. (ASE) and Digi-Key. Taiwan's ASE is EPC's backend provider, while Digi-Key represents its distribution partner.

EPC has developed a GaN-on-silicon process. In its technology, a aluminum nitride isolation layer is sandwiched by GaN and a silicon substrate. Its products are produced in a standard silicon CMOS foundry on 150-mm wafers.

Unlike most rivals, the company is using an enhancement-mode GaN technology. ''Depletion mode devices are less suitable for power applications than enhancement-mode devices,'' Alex Lidow said.

''Depletion mode devices are normally on until voltage is applied to the gate electrode. Enhancement mode devices are normally off,'' he said. ''Enhancement mode devices are generally preferred in power circuits because, when a power circuit is turned on, the enhancement mode devices initially do not conduct current. In the case of depletion mode devices, when the system is turned on, there is a short circuit between input and output until voltage is applied to the gate electrode.''

EPC claims its GaN technology can save power and cost. For example, a dual processor server card consumes approximately 450 Watts of power. Approximately 160 Watts are consumed by power conversion. EPC claims its GaN technology can reduce total server power requirements by about 18 percent.

The on-resistance for a given device area is a key determinant of product cost. EPC claims its products have the same on-resistance and are smaller than the best silicon parts available.

Its products range from 40 Volts to 200 Volts, and 4 milliohms to 100 milliohms. The products are priced between $0.80 and $5.00 in 1,000-unit quantities and are immediately available through Digi-Key.

EPC's products will cover 90 percent of the existing power MOSFET market by the end of 2010. EPC is now shipping sample quantities of power transistors to select strategic customers. EPC will start delivering product to general customers beginning in Q1 2010

Still, the big question is clear: Will EPC's products disrupt the status quo and replace the lowly power MOSFET? And what about IR's entry into the GaN fray?

''Additional entrants into the GaN transistor market will only accelerate the transition by increasing the customers' confidence in their decision to switch technologies,'' Alex Lidow contends. ''Power MOSFET producers have mature technologies and supply chains, and will fight hard to avoid displacement by a new technology. EPC's strategy is to initially address applications where power MOSFETs simply cannot perform.''