Emerging Research Nanoelectronic Devices and Interfaces Between Wet and Dry Science

Victor Zhirnov
Semiconductor Research Corporation / USA

The Emerging Research Devices Group of the International Technology Roadmap for Semiconductors provides assessments of alternative concepts for memory and logic devices that would, if successful, substantially extend the Roadmap beyond CMOS. For example, there are several device candidates based on beyond-CMOS nano-electronics, e.g., spin-based, NEMS, nanoionic elements, etc. A detailed assessment of different operation parameters of emerging research devices has resulted in the observation that, while we have several viable emerging memory technologies, viable emerging logic technologies for beyond CMOS have not yet been identified. There are many challenges that must be overcome if physical state variables other than the electron charge are contemplated for use to represent system state. For example, if electron spin is used as a state variable, then either high external magnetic fields are required for single-spin devices, or, if multiple spins are used, scalability is impacted. On the other hand, optical-based computational systems, while offering advantages for communication, require switching devices significantly larger than and with higher switching energy than electron-based devices; principally due to the inherent non-locality of light. Nanoionic devices for logic applications might show promise for sub-10nm regime operations. It will be argued that the use of charged particles whose mass is substantially greater than that of electron have the potential to offer better control of computational state for devices with feature sizes in the 1-nm regime, i.e. beyond the projected limits for electron device scaling. A critical issue here is the ability to achieve control of the properties of ‘chemiconductor’ materials that is comparable to that realized in conventional semiconductors.

Fluid nanoelectonics utilizing liquid media may offer another promising path to replace the foundation of today’s computing technologies. It is known that ions in liquid electrolytes play an important role in biological information processors such as the brain or living cells. It will be argued that the living cell can be conceptualized as a general-purpose computer with molecular-scale components. Although it is at a very early stage, fluid nanoelectronics could someday allow for very powerful and energy-efficient computing. Fluid nanoelectronic systems could be reconfigurable, with individual elements strung together to create wires and circuits that could be reprogrammed (this is in contrast to conventional electronic circuits, which are hardwired by a fixed network of interconnects).