Have We Reached The Limits Of Silicon?
from the are-we-there-yet? dept
The growing demand for greater mobile computing power is rapidly transforming how the semiconductor industry needs to think about designing chips to meet the performance requirements for mobile devices. With GHz-level processor speeds and several GB of data storage, current smartphones have the computational power of high-end desktop computers from just ten years ago. As we move towards smaller and faster computing devices, the use of silicon in chips is making it increasingly difficult to uphold Moore’s Law, not only in terms of the laws of physics, but also in terms of economics. However, it’s worth mentioning that claims of the end of Moore’s Law have been going on for years and are greatly exaggerated when you consider that Moore’s Law keeps getting redefined as time passes. In the end, it really isn’t as big a deal as the press makes it out to be.
Recently, TSMC’s vice president of research and development, Chiang Shang-yi, said that current silicon chip technology should be able to sustain Moore’s Law for another decade, but he also pointed out that Moore’s Law could come to an end sooner due to economic rather than technological reasons, as it becomes increasingly expensive to develop and manufacture next-generation chips. Even so, he’s not really that worried, as his take-home message is that after the end of Moore’s Law (whenever that may happen), there are still many more years of what he calls “More Than Moore” technologies, and then even more years of system integration improvements.
Kevin Kelly has presented an interesting and compelling take on Moore’s Law — basically saying that the exponential progress is inevitable in technologies that scale down to microscopic or even nanoscopic sizes. He also points out that once the exponential growth of a technology starts to plateau, we will naturally shift our focus to other alternative technologies, which may subsequently experience their own exponential growth and establish new “laws.” He even suggests that Moore’s Law could be redefined as a larger trend that can continue indefinitely, encompassing several smaller, overlapping technology trends.
As “the end of Moore’s Law” looms ahead, it would appear that people are beginning to shift some of their focus to new alternative technologies that could potentially replace silicon in chips. Here are just a few of the latest technologies that are being investigated for potential use in microelectronics:
In the past couple of years, graphene has been touted as a potential replacement for silicon. Graphene, a single-atom-thick layer of carbon atoms bonded together in a graphitic structure, has been widely studied for its interesting mechanical, chemical, and electronic properties. Graphene sheets have carrier mobilities that are hundreds of times greater than that of silicon, making them ideal for faster chips. However, a major problem with graphene is that it tends to get very hot when devices are operated at the saturation current limits. Recently, it was demonstrated that memristors — resistors with memory — could perform logic operations, and it has even been predicted that memristor-based processors could one day replace the silicon in e-reader displays, as well as in computers. Diamond, an excellent thermal conductor, can be turned into a semiconductor with the right impurities, and it could be used to make high-performance chips that won’t need power-draining cooling systems. However, it is difficult to make diamond wafers large enough for mass production.
Of course, none of these technologies are close to being ready for commercialization yet, but they’re a glimpse of what could be the continuation of Moore’s Law in its broader sense. In the meantime, companies will try their best to stretch out current technology for as long as it makes sense to.