Next week Intel will outline small but important changes to the way it expects to make transistors after 2005, as it continues to battle the laws of physics to build ever-faster processors.

The changes will affect both the structure of transistors and the materials used to make them, and will be described by Intel engineers at next week's International Electron Devices Meeting in Washington, DC.

The changes could be introduced as soon as 2005, and attempt to address two of the biggest obstacles to building faster PC chips: heat and power consumption.

"We can make transistors that are very small and very fast, but that's not good enough any more," said Gerald Marcyk, director of Intel's components research lab. "The problem is that the power consumption is rising exponentially."

Transistors are, in essence, miniature electrical switches that can be turned 'on' or 'off' to represent the ones and zeros of binary computer code. Increasing the number of transistors on a chip while decreasing their size has been a key factor in developing ever-faster chips.

Today's Pentium 4 contains around 42 million transistors. With the number of transistors in a microprocessor doubling approximately every two years, the count is expected to hit one billion in the second half of the decade, resulting in microprocessors that have 25 times the computing power as today's chips, Marcyk said.

At the same time, transistors have been shrinking. Already they include structures that are just 70 nanometres wide, or 100 times thinner than a human hair. By 2007 those structures are expected to reach 20 nanometres or smaller.

As transistors get smaller, however, they start to leak electricity, and can do so even when a computer is switched off. For example, electricity can escape through the thin layer known as the gate oxide, which separates the transistor gate from other parts of a chip. Leaky chips require more current to switch the transistors on and off, which in turn increases the amount of heat generated.

One of the papers to be presented next week proposes using a new class of material, called a High K gate dielectric, to replace the silicon dioxide used today. Intel doesn't know yet exactly which material it will use — aluminium oxide and titanium oxide are among the contenders — but it has discovered that a new material can cut leakage by a factor of 10,000, according to Marcyk.

Users aren't likely to shell out money on faster chips if there aren't any applications that make use of the extra power, but many in the industry believe such software may not be too far over the horizon, in the shape of new interface technologies that let people control computers using speech or facial gestures, for example.