Energy-efficient transistors

Rob Willoner: Hello. I'm Rob Willoner. I'm a technology analyst at Intel, and I'm going to talk to you about energy efficient transistors.

Everybody wants more energy efficient PC's and servers, and we all want to reduce our carbon footprint. Yet, everybody wants more performance. How do we get there? Engineers are tackling this problem at many levels: at the operating system level, at the application level, through new packaging technologies, and through innovations in micro architecture and circuits. Today, we're going to talk about a new transistor technology.

Transistors are the foundations of all computer chips. If you look at a chip, it consists of a set of transistors tied together with wires or interconnects. Today's microprocessors have hundreds of millions of transistors. The 65 nanometer Core two Duo has 290 million transistors, and its successor, the 45 nanometer version, will have 410 million transistors. But in order to pack more transistors on a chip, we have to make each one of them smaller.

Let's look at an earlier generation transistor. The source and the drain between which current flows are quite far apart. The gig, which controls the current, is separated by a rather thick insulator. As we move from 65 to 45 nanometers, this distance becomes much less and this layer becomes much thinner. This provides opportunities for electrons to travel from one point to another when they're not supposed to, and this leads to unwanted leakage power.

Think of a leaky faucet. It drips water, even when it's turned off. Now, imagine that all the faucets in your house were leaky. This is the situation we were faced with. If you look at the leakage from a single transistor, it's very small. It's measured in nano amps. But, if you have hundreds of millions of transistors on a chip, it adds up and becomes quite problematic.

Intel is attacking this problem by replacing key components of the transistor with new materials. We're replacing the insulator with a Hi k material, and the polysilicon gate is being replaced by a metal material. This combination allows us to make this insulator much thicker, thereby reducing leakage. Overall, this enables a greater than 20 percent improvement in transistor switching speeds, and reduces power in various ways, including a 10 X reduction in gate offsite leakage. Energy efficient transistors lead to energy efficient computers.