Towards Ultimate Scaling – Semiconducting Nanowires and Molecular Electronics
IBM Research GmbH, Säumerstrasse 4, CH-8803 Rüschlikon, Switzerland
As device dimensions continue to shrink into the nanometer length-scale regime, conventional semiconductor technology (CMOS) will be approaching fundamental physical limits. New strategies, including the use of novel materials and 1D-device concepts, innovative device architectures, and smart integration schemes need to be explored and assessed. They are crucial to extend current capabilities and maintain momentum beyond the end of the technology roadmap time frame (post-CMOS era).
In this presentation two possible candidates of ultimate and post-CMOS technologies, such as semiconducting nanowires and molecular electronics will be covered. Owing to their potential compatibility with existing CMOS technology, silicon (Si) nanowires (NWs) are considered to be one of the most promising candidates for future logic and memory elements. Results on lateral and vertical Si NW field effect transistors (FETs) based on doped and intrinsic NWs will be presented. In addition, we report on vertical integration of single surround-gated Si NW FETs that operate as classical FET and as impact ionization FET with inverse sub-threshold slopes below the room temperature limit.
The second part will cover molecular electronics which is aimed at the use of individual or small ensembles of molecules as functional building blocks in electronic circuits. We are investigating the charge transport through individually contacted and addressed molecules using the mechanically controllable break-junction technique. Using this technique, we demonstrated reversible and controllable switching between two distinct conductive states of a single molecule thereby successfully accomplishing memory operation on a single-molecule level. We could show that this molecular conductance switching has truly an intrinsically molecular origin.