3-D TRANSISTORS : AN INTEL BREAKTHROUGH
by Megha Mehta, BVCOE
Intel’s market share of the chip industry has been phenomenal- with some even calling the figures ‘grotesque’ and ‘obscene’. To further that lead in the smartphones and tablet segment, the semiconductor giant will launch a new breed of transistors in April 2012.
Moore's Law, more a manufacturing rule of thumb than a scientific law, predicts that roughly every two years, the number of transistors on a chip doubles. This, while ensuring that the performance levels never fall and the power consumption is kept to a minimum. Innovations in the chip technology determine the device performance and the power it consumes. After chalking out several strategies for creating ever-shrinking microprocessors and memory units, in keeping with the law, it is becoming more and more difficult to keep up with it. As the size of the transistors keeps shrinking, it's getting harder and more expensive to keep that scaling going.
Sighting the end of Moore’s law nearly a decade back, Intel took it upon itself to extend it by means of redesigning the current-carrying channel of the MOSFET, which conducts the current in ‘one dimension’. Hence, the ‘planar’.
What has it come up with, you ask? The ‘Tri-Gate or 3-D transistor’, which is really the gate cut on the plane to surround a three dimensional source-drain channel, instead of the traditional placing of the gate on the one dimensional channel. As a result, the gate area increases – offering 37 percent faster switching at the same power or optimum performance at half the power consumed by existing chip designs. This is ideal for shrinking mobile devices with higher performance demands. Point to be noted, as the reader will discover later.
The source-drain channel, now extended to three sides.
Image courtesy: technology.ezinemark.com
The etching process at such a scale needs to be precise and since for increasing current, one can't make the channel wider, the solution is to go vertical. This traps more surface area between the channel and gate, and therefore allows better control of its characteristics.
But the classic process of depositing and etching away material to create the integrated circuit does not support the stacking up of gates. Thus, making the current flow in three channels instead of one is the solution that Intel has proposed, with the first batch chips using the 3 D transistors coming out in April 2012, codenamed Ivy Bridge.
According to Intel: "The additional control (3 D channel) enables as much transistor current flowing as possible when the transistor is in the 'on' state (for performance), and as close to zero as possible when it is in the 'off' state (to minimize power), and enables the transistor to switch very quickly between the two states (again, for performance)."
Why the 3D transistors part-2. Work on the 3 D transistor design has been on for over a decade in other semiconductor companies as well. But Intel will have a three year lead if the launch takes place as timed. Industry insiders feel that it is timed to mark Intel’s foray into the smartphone and tablet world, from which it has been curiously and largely absent. Its Atom microprocessor, used in netbooks continues to be outperformed by the designs of the UK-based semiconductor giant ARM Holdings, which owns a monstrous 95% of the market share in chips for most mobile devices. With the tablet-smartphone market catching the consumer’s attention like never before, this has sent the competitors into a tizzy. The industrial demand for the sturdier desktop computers is still greater than that for personal consumption, which gives Intel a monstrous lead in the segment. But with the rapid invasion of the consumer market by tablets, it becomes imperative for Intel to gain a foothold in the mobile device market. The last few years have seen Intel promising x86 mobile devices, but it never quite materialised. Fact remains- Intel’s x86 processor has not found a place in smartphones on a massive scale. Intel has been working on Android 4.0- Ice Cream Sandwich- to add optimizations to finally make it Intel x86 ready, hoping to launch their first x86 powered smartphone in the first half of 2012. Meanwhile, the 3D transistors will perhaps first find place in memory components before anything else.
Considering how a good number of software applications and operating systems are ARM-based and too huge for manufacturers and designers alike to migrate to new chip designs, it remains to be seen if the 3-D transistors live up to their promise.