It seems that the semiconductor industry can’t go a year without someone raising the tired old flag that is the impending doom of Moore’s Law. Nearly every year there’s a group of people out to see it finally meet its end although to what purpose I could not tell you. However as an industry observer will tell you these predictions have, for the past 5 decades, proved to be incorrect as any insurmountable barrier is usually overcome when the requisite billions are thrown at the problem. However we are coming to a point where our reigning champion behind Moore’s Law, namely planar transistors built on silicon, is starting to reach the end of its life and thus we have been searching for its ultimate replacement. Whilst it seems inevitable that a new material will become the basis upon which we build our new computing empire the question of how that material will be shaped is still unanswered, but there are rumblings of what may come.
For the vast majority of computing devices out there the transistors underneath the hood are created in a planar fashion, I.E. they essentially exist in a 2 dimensional space. In terms of manufacturing this has many advantages and the advances we’ve made in planar technology over the years have seen us break through many barriers that threatened to kill Moore’s Law in its tracks. Adding in that additional dimension however is no trivial task and whilst it’s not beyond our capability to do, indeed my computer is powered by a component that makes use of a 3D manufacturing process, but applying it to something as complicated as a CPU requires an incredible amount of effort. However the benefits of doing so are proving to be many and the transistor pictured above, called a Quantum Well Field Effect Transistor (QWFET), could be the ram with which we break through the next barrier to escalating Moore’s Law.
The main driver behind progress in the CPU market comes from making transistors ever-smaller, something which allows us to pack more of them in the same space whilst also giving us benefits like reduced power consumption. However as we get smaller issues that could be ignored, like gate leakage back when we were still at the 45nm stage, start to become fundamental blockers to progress. Right now, as we approach sizes below 10nm, that same problem is starting to rear its head again and we need to look at innovative solutions to tackle it. The QWFET is one such solution as it has the potential to eliminate the leakage problem whilst allowing us to continue our die shrinking ways.
QWFETs are essentially an extension of Intel’s current FinFET technology. In the current FinFETs electrons are bounded on 3 sides which is what helped Intel make their current die shrink workable (although it has taken them much longer than expected to get the yeilds right). In QWFETs the electrons are bounded on an additional side which forms a quantum well inside the transistor. This drastically reduces the leakage which would otherwise plague a transistor of a sub-10nm size and, as a benefit, significantly reduces power draw as the static power usage drops considerably.
This does sound good in principle and would be easy to write off as hot air had Intel not been working on it since at least 2010. Some of their latest research points to these kinds of transistors being the way forward all the way down to 5nm which would keep Moore’s Law trucking along for quite some time considering we’re just on the cusp of 14nm products hitting our shelves. Of course this is all speculative at this time however there’s a lot of writing on the wall that’s pointing to this as being the way forward. If this turns out to not be the case then I’d be very interested to see what Intel had up their sleeves as it’d have to be something even more revolutionary than this.
Either way it’l be great for us supporters of Moore’s Law and, of course, users of computers in general.