Intel shows off next generation transistors

Computers the world over are about to get a makeover. Intel, the world's largest computer chip maker, announced on Saturday that its next generation transistors will have metal - not silicon - gate electrodes. They will also have insulating walls made of a "high-K" hafnium (wikipedia) compound, which is transparent to electric fields, instead of silicon dioxide.

reposted from: NewScientist.com news service
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The changes mean that the 45-nanometre transistors on Intel's next suite of computer processors will not only be faster and smaller than today's 65-nanometre ones, they will also be more power efficient. That combination has been difficult to achieve in the past.

"The implementation of high-k and metal materials marks the biggest change in transistor technology since the introduction of polysilicon gate transistors in the late 1960s," says Intel co-founder Gordon Moore.

The new transistors will make their way into Intel's next generation products, currently codenamed "Penryn", which include the Core 2 Duo, Core 2 Quad and Xeon processors. These will run Windows Vista, Mac OS X, Windows XP and Linux.

Leaky materials

Intel first announced that it would start using the new materials at the end of 2003 (see Intel claims plug for leaky chips). But on Saturday it announced that manufacturing will begin later in 2007, with the first products available in 2008.

"It's no longer a research project, it's real," says Dan Hutcheson, an analyst with VLSI Research in California, US. "This is a really big breakthrough."

A transistor consists of an electrode that switches the current on and off within a "channel" using an electric field. In the past, to make the transistor switch faster, and thereby up its performance, chip makers shortened the electrode and thinned the insulating wall that separates it from the channel.

This is far from ideal, as thinning the wall causes current to leak from the channel into the electrode, wasting heat and electricity. Furthermore, it means more current leakage than the transistor could handle.

Switching speed

Now, in an effort to continue shrinking and speeding up its transistors, Intel has come up with an insulator that transmits a fast-switching electric field even at a relatively large size. The exact composition of this "high-k" material is a secret, but Intel says that it contains hafnium. It is claimed to increase transistor switching speed by 20% and leak five times less current.

In 2003, Intel also had to tweak its process to start making 90 nanometre transistors. Its secret then was to use "strained silicon" in its transistors (see Secret of strained silicon chips revealed). This increased the speed at which current flowed, although Hutcheson says that advance was "a walk in the park" compared with achieving today's leap to high-k insulators.

The change in insulator has also led to a change in the gate electrode material. When high-k materials are deposited next to an electrode made of polysilicon, defects normally arise at the boundary. But this effect disappears when a metal gate is used instead.

Using the new 45 nanometre transistors, dual-core processors will contain 400 million transistors, while quad-core will contain 800 million.