Future Trends in Microelectronics: Up the Nano Creek

Molecular Meso- and Nanodevices: Are the Molecules Conducting?

N. B. Zhitenev

Bell LaboratoriesLucent Technologies, 600 Mountain Ave., Murruy Hill, NJ 07974, U.S.A.

1.   Introduction

As Si-based microelectronics approaches fundamental limits to continued scaling, organic-inorganic hybrid electronics has become one of several options that are proposed to not only extend performance but increase functionality.^1-3 Molecular electronics is projected to introduce the vast capabilities of synthetic chemistry into the realm of nanoelectronic devices. The rich phenomena of self-organization, self-assembly and area-specific growth that occur at the molecular scale are proposed^4-6 to replace some of the most prohibitive and expensive processes in fabrication, such as nanopatterning⁷ and film growth. Yet, despite noticeable progress, it is premature to claim that a fundamental understanding of the conductance mechanisms in nanoscale molecular organic or inorganic devices has been achieved; certainly no feasible manufacturing scheme is available or even on the horizon.

The general approach for molecular device fabrication is to perform the most critical patterning of nanometer features without molecules, to assemble the molecules, and then to complete the structure with a hopefully noninvasive processing step. Material and chemistry unpredictability, as well as diffusion and defect generation in the different fabrication processes, inevitably result in significant variations in the final ...