Intel puts Tri-Gate transistor on fast track

Intel says that its Tri-Gate transistor, a futuristic transistor that will let electricity flow more freely inside chips, is moving closer to reality.

The Tri-Gate transistor, one of the tools that may let Intel continue to follow Moore's Law in the second half of the decade, has been placed on the "pathfinder" development path at Intel, said Ken David, co-director of components research in the Technology Manufacturing Group at Intel. That means that it is one of a select few design alternatives that will get incorporated into chips by 2007.

"We've moved beyond the research stage and are in the development stage," David said. "Within a year or two we will narrow to a single approach and go with that."

The company presented a paper this week on the transistor, along with others on breakthroughs in incorporating radios onto chips, at the Very Large Scale Integration (VLSI) Technology Symposium in Kyoto, Japan.

Harnessing electricity is one of the major problems facing chip designers today. Under Moore's Law, the number of transistors on a chip double every two years, a phenomenon often accomplished through shrinking the size of the transistors--tiny on-off switches that in concert perform calculations.

Unfortunately, small transistors leak electricity, something that leads to poor battery life and excess internal heat.

Tri-Gate transistors ameliorate that situation by increasing the surface area of the gate, which controls the flow of electricity.

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Traditional gates are flat, and electricity flows like a stream directly beneath it. Tri-Gates are shaped like a tunnel and electricity flows on the internal surface of the arch. More surface area leads to a more stable flow of electricity, which in turn can lead to greater performance, less leakage or both.

Intel has made Tri-Gate transistors with gates measuring 30 nanometers in length in its labs, David said. The company is looking for a new type of transistor for chips that will come with features measuring 45 nanometers on average. (A nanometer is a billionth of a meter.) These chips will debut commercially in 2007. At this time, however, the transistor gate length will be only around 20 nanometers, he said.

"This is a whole different approach to transistor scaling," said Nathan Brookwood, an analyst at Insight 64. IBM and Advanced Micro Devices are working on "finfet" transistors, which have two gates.

The only other alternative Intel is looking at is improving current planar transistors, David said. Both alternatives are part of the Terahertz transistor family, the name for a group of future transistors that embody specific characteristics. The definition of Terahertz appears to be shifting a bit over time, Brookwood said.

In other VLSI papers, the Santa Clara, Calif.-based chipmaker showed how it has developed a 10GHz agile frequency synthesizer on silicon that helps tune a radio and lock it onto a frequency. At these speeds, the experimental synthesizer could make it easier one day for wireless laptops to find a clear connection not crowded by other users, said Krishnamurthy Soumyanath, director of communications circuit research at Intel. Eventually, fast synthesizers could also allow laptops to hop smoothly across different protocols and frequencies.

Additionally, the company showed off a paper for a 5GHz transformer-coupled voltage controlled oscillator, a component that goes inside the synthesizer, Soumyanath said.

These parts are made on silicon chips, helping to cut costs. Radio parts historically have been made on analog chips, which often use specialized and expensive circuitry.

"Traditional radio circuits are boutique circuits," he said. "Analog is never going to go away, but you want to increase the amount of digital circuitry as much as possible."