Future Trends in Microelectronics: Up the Nano Creek

Alternatives to Silicon: Will Our Best Be Anywhere Good Enough in Time?

M. J. Kelly

Centre for Advanced Photonics and Electronics, Dept. of EngineeringUniversity of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, U.K.

1.   Introduction

The 2005 edition of the International Technology Roadmap for Semiconductors¹ draws attention to the need for post-CMOS devices within a decade. I want to argue from several premises that we are most unlikely to be ready in time. If we assume that the ITRS will be as generally accurate in the near future as it has proved in the recent past, then 45 nm and even 32 nm CMOS seem destined to arrive on time. (See Section 5 if this assumption is incorrect.) The individual transistors have been demonstrated for some years and large-scale integration has also been demonstrated. It is only the further grind of refining the technology that is left, and no one has shown any show-stoppers: the predicted ones seem to have been overcome, even if the heat dissipation means that not all devices are clocking as fast as they might.

The Roadmap is fairly sanguine about all the radical alternative technologies, but the longer CMOS continues, the harder it will be for any alternative device ideas to be good enough to take up from CMOS and continue the progress of Moore’s law for computing power. Only two, engineered tunnel barriers and nano-floating gates, seem to offer even the prospects of complementing CMOS in the future. All the others will fall away because of ...