Rensselaer student invents alternative to silicon chip

May 13, 2008
Weixiao Huang
Weixiao Haung and new GAN transistor. Credit: Rensselaer Polytechnic Institute

Even before Weixiao Huang received his doctorate from Rensselaer Polytechnic Institute, his new transistor captured the attention of some of the biggest American and Japanese automobile companies. The 2008 graduate’s invention could replace one of the most common pieces of technology in the world—the silicon transistor for high-power and high-temperature electronics.

Huang, who comes from humble roots as the son of farmers in rural China, has invented a new transistor that uses a compound material known as gallium nitride (GaN), which has remarkable material properties. The new GaN transistor could reduce the power consumption and improve the efficiency of power electronics systems in everything from motor drives and hybrid vehicles to house appliances and defense equipment.

“Silicon has been the workhorse in the semiconductor industry for last two decades,” Huang said. “But as power electronics get more sophisticated and require higher performing transistors, engineers have been seeking an alternative like gallium nitride-based transistors that can perform better than silicon and in extreme conditions.”

Each household likely contains dozens of silicon-based electronics. An important component of each of those electronics is usually a silicon-based transistor know as a silicon metal/oxide semiconductor field-effect transistor (silicon MOSFET). To convert the electric energy to other forms as required, the transistor acts as a switch, allowing or disallowing the flow of current through the device.

Huang first developed a new process that demonstrates an excellent GaN MOS (metal/oxide/GaN) interface. Engineers have known that GaN and other gallium-based materials have some extremely good electrical properties, much better than silicon. However, no useful GaN MOS transistor has been developed. Huang’s innovation, the first GaN MOSFET of its kind in the world, has already shown world-record performance according to Huang.

In addition, Huang has shown that his innovation can integrate several important electronic functions onto one chip like never before. “This will significantly simplify entire electronic systems,” Huang said. Huang has also designed and experimentally demonstrated several new novel high-voltage MOS-gated FETs which have shown superior performance compared to silicon MOSFET in terms of lower power consumption, smaller chip size, and higher power density.

The new transistors can greatly reduce energy loss, making energy conversion more efficient. “If these new GaN transistors replaced many existing silicon MOSFETs in power electronics systems, there would be global reduction in fossil fuel consumption and pollution,” Huang said.

The new GaN transistors can also allow the electronics system to operate in extremely hot, harsh, and high-power environments and even those that produce radiation. “Because it is so resilient, the device could open up the field of electronic engineering in ways that were not previously possible due to the limitations imposed by less tolerant silicon transistors,” he said.

Huang has published more than 15 papers during his time as doctoral student in the Department of Electrical, Computer, and Systems Engineering at Rensselaer. Despite obvious difficulties, his parents worked tirelessly to give Huang the best possible educational opportunities according to Huang. And when school wasn’t enough, Huang’s father woke him up early every morning to practice mathematical calculations without a calculator, instilling in Huang a lifelong appreciation for basic, theoretical mathematics and sciences.

He received a bachelor’s in electronics from Peking University in Beijing in 2001 and a master’s in physics from Rensselaer in 2003. He will receive his doctorate from Rensselaer on May 17, 2008 and plans to work as a device engineer in the semiconductor industry.

Source: Rensselaer Polytechnic Institute

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5 / 5 (3) May 13, 2008
Wow, that's really impressive. I would like to see a side by side comparison of this new technology next to silicon.
5 / 5 (2) May 13, 2008
This guy needs to be the chief tech at his own startup. Guys like him instantly qualify for funding here in the Valley. He just needs to partner with a specialized business veteran and away he goes.
2.7 / 5 (3) May 13, 2008
This appears to just be a better power transistor; useful for things like speakers, switching mode power supplies(especially high frequence ones) and other common components but it does not appear to do anything for ICs(as the article's name implies).
1.7 / 5 (3) May 13, 2008
It's a poorly written article that gives no idea how his design accomplished its' goal.
2.8 / 5 (4) May 13, 2008
Hrmm, GaN transistors have been around for a while. Not sure why this is news.
2.3 / 5 (4) May 14, 2008
Silicon in the Earth's Crust: 277100 ppm
Gallium in Earth's Crust: 18 ppm

I see a bottleneck that prevents it from being a pure substitute for all our needs.
4.5 / 5 (2) May 14, 2008
Yes this is not a regular electronics transistor. Power electronics circuits can also be used for variable speed drives, if developed for ultra high current applications it could be very lucrative. Large variable speed drives sell for $100 per horsepower.
4.5 / 5 (2) May 14, 2008
Silicon in the Earth's Crust: 277100 ppm
Gallium in Earth's Crust: 18 ppm

I see a bottleneck that prevents it from being a pure substitute for all our needs.

On the contrary, 18 ppm is A LOT.

Copper has an average abundance of ~63 ppm and we manage to produce 14.6 million metric tonnes per year, selling at ~4$/lb. That's 2 kg for every man woman and child on the Earth, per year. Unlike so many things which are a waste of time, resources and the environment to recycle, copper scrap is very lucrative and most of it gets recycled one way or another. Sometimes druggies will even steal copper cable and copper scrap to recycle it!

Silver has an average crustal abundance of 0.08 ppm, or ~225 times more rare than gallium. We manage to mine 20 000 metric tonnes a year of silver. And silver isn't even particularly useful for anything; a little bit finds its way into special high capacity batteries, solder, catalysts and the like but most of it is just pissed away on pretty things which serve no purpose or can easily be substituted for like bars, rings, piercings, utensils, commemorative coins, medals, pins.
5 / 5 (3) May 14, 2008
This appears to just be a better power transistor; useful for things like speakers, switching mode power supplies(especially high frequence ones) and other common components but it does not appear to do anything for ICs(as the article's name implies).

Well in my industry (Heavy Mobile), I'm sick of using mechanical relay's for high power situations. Having a Solid State device that can handle high power loads without generating a ton of heat and wasted energy would be great.
3 / 5 (1) May 14, 2008
hate to rain on his parade...but physorg news85411129 & some others have in the recent not so past reported on that...A} subcategories Published: 13:18 EST, December 15, 2006, news85411129
Panasonic Develops New Gallium Nitride Power Transistor with Normally-off Operation
Panasonic today announced the development of a Gallium Nitride (GaN) power transistor with normally-off operation. This device is the world's first demonstration of the conductivity modulation in GaN as a novel operating principle leading to low on-state resistance. The new GaN transistor enables low-loss and high-voltage power switching devices. & then this...
Switch-mode power supplies, such as this 350%u2009W supply, are used to convert AC mains into DC outputs for computers and other consumer and industrial electronics products. Today all of the manufacturers of these supplies use SiC and silicon devices, but they will also have the option to select GaN-on-sapphire equivalents by the end of the year, which are being developed by Velox Semiconductor. All three types of device tend to be housed in TO-220 packages. If silicon or SiC devices are used, one of the electrodes must be positioned at the bottom of the device and make the contact with the frame. When GaN is used both contacts are made on the top of the device, making the frame isolated. This advantage stems from the excellent insulation properties of sapphire, which can provide more than 2400%u2009V of isolation from the frame if the wire bonds are made to the legs that are not connected with the frame. Credit: Velox. GaN Schottky barrier diodes threaten to overturn SiC...Manufacturers of switch-mode power supplies can get exactly what they want with Velox's GaN-on-sapphire Schottky diodes: the performance of SiC at a fraction of the price. Michael Murphy, Linlin Liu, Milan Pophristic, Boris Peres detail the advantages of the technology. Soaring energy prices and an increased awareness of environmental issues are spurring the development of products that consume less energy. For computers and other consumer and industrial electronic products, one area with the potential for improvement is the switch-mode power supplies (SMPSs) that convert AC mains into various DC formats. Ideally, these supplies would now be delivering higher efficiencies through the employment of SiC high-voltage Schottky barrier diodes, but the high price of these devices is preventing them from displacing the less efficient silicon equivalents that still dominate the high-power semiconductor market. However, it will soon be possible to enjoy the benefits of a wide-bandgap semiconductor %u2013 high breakdown fields, good thermal conductivities, and high electron mobilities and saturation drift velocities %u2013 by turning to GaN instead. On sapphire substrates, GaN promises to be a much cheaper alternative to SiC. This combination of materials may raise a few eyebrows, because it is widely believed to suffer from sapphire's low conductivity %u2013 something that ultimately leads to poor thermal resistances and hot, unreliable devices. But at Velox Semiconductor, located in Somerset, NJ, we have demonstrated the folly of this argument with GaN-on-sapphire diodes that are incorporated in an insulating frame. The compatibility with an insulating frame is a big advantage over SiC, because it reduces the cooling demands of the heat sinks employed in the SMPSs. In these modules we have found that our devices deliver efficiencies comparable to SiC and significantly better than those of silicon.

The manufacturing cost-savings over SiC equivalents stem from cheaper, larger substrates and a lower epiwafer growth temperature. We are building our devices on 100%u2009mm sapphire, which has primarily been developed for the multibillion-dollar GaN LED industry as it transitions away from 2 and 3%u2009inch wafers. Multiple vendors are now supplying the larger-sized material, and prices are falling thanks to healthy competition and continuous manufacturing improvements. There might also be an option of scaling to even larger substrates in the near-term, as 150%u2009mm research and development material is already available from leading manufacturers. In contrast, 100%u2009mm SiC substrates are only available in limited quantities at outrageous prices, so manufacturing and development is undertaken on the 75%u2009mm platform. This smaller size is still pricey and we have found that its cost per unit area is typically four times that of sapphire.
4 / 5 (1) May 15, 2008
Well in my industry (Heavy Mobile), I'm sick of using mechanical relay's for high power situations. Having a Solid State device that can handle high power loads without generating a ton of heat and wasted energy would be great.

Sure; there's nothing wrong with that at all. But you're looking for power output in watts and I'm looking for power output in FLOPS, which is why the article's title was a setup for being let down.
5 / 5 (2) May 15, 2008
The best chips are still potato-based.

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