FinFETs Extend Intel's Technology LeadMay 6, 2011
Author: Tom R. Halfhill
Cadillac introduced tailfins to evoke high-tech style in the 1950s, but Intel's new finned transistors are far from cosmetic. Purely functional, highly efficient, yet equally brash, these fin-shaped field-effect transistors (finFETs) are sure to be copied as widely as Cadillac's useless appendages—and they will play a similar role in defining an era.
Intel calls finFETs "tri-gate" transistors, touting them as the first true three-dimensional devices built on planar integrated circuits. A tri-gate transistor folds a conventional planar gate into an inverted U-shaped fin that protrudes above the silicon substrate. By coating all three sides of the fin with metal, Intel builds a 3-D gate structure that has much more volume than a planar gate while still squeezing into the same horizontal space.
Tri-gate transistors can handle greater drive currents, allowing higher clock frequencies. They can switch states at a lower threshold voltage without sacrificing as much switching speed, which reduces dynamic power consumption. In addition, the thicker gate leaks less current, reducing static power. As always, chip designers can trade off these factors in various ways to achieve the best balance of performance and power consumption for the target application.
Intel will use the new transistors for both logic circuits and memory arrays in all its microprocessors built in the next-generation 22nm process, which debuts later this year. The company has demonstrated PC and server processors built with the new technology and is already shipping samples to OEMs for system design. Volume production is scheduled to begin in the fourth quarter and ramp quickly next year. And Intel isn't hedging its bets: contrary to rumors, the new chips will use tri-gate transistors universally, abandoning planar transistors forever.
FinFETs reinforce Intel's significant lead in chip fabrication. In addition to using new transistors, Intel is moving to the 22nm mode about two years ahead of the rest of the industry, which is only now beginning the transition to 32/28nm technology. The independent foundries serving virtually all of Intel's competitors have no plans to use finFETs before the 14nm node—and adoption may be tentative even then. It appears that Intel has gained a head start of at least four years, much as the company achieved in 2007 by introducing high-k metal-gate (HKMG) transistors at the 45nm node. FinFETs could boost Intel's position in the mobile and consumer markets, where it needs an edge to overcome entrenched competitors. —Tom