ELSEVIER MicroeloetronieEngineering 35 (1997) 281-284 MICROELECTRONIC ENGINEERING AFM-based fabrication of lateral single-electron tunneling structures for elevated temperature operation L. Montelius, T. Junno, S.-B. Carlsson and L. Samuelson Department of Solid State Physics & The Nanometer Structure Consortium, Lund University, P.O. Box 118, 221 00 Lund, Sweden In this paper we will report a method that allows controlled positioning of individual nanoparticles between e-beam defined metal electrodes using AFM technique, having not only the imaging capability in the AFM for inspection of the positioning, but also in-situ electrical monitoring of the assembly procedure. This means that an electrical signal is recorded when an electrical link between the lateral metal electrodes, via the positioned particles, is established. 1. INTRODUCTION In recent years the interest for devices based upon the properties of low- dimensional structures has increased substantially. Devices utilizing single electron tunneling (SET) phenomena are possible candidates for single electron memories that might allow room temperature operation. Coulomb blockade effects have been observed at low temperatures in numerous tunnel barrier structures for both metals and semiconductors [1-3]. The first observation of Coulomb charging effects at room temperature was obtained by creating a vertical double barrier structure using the tip of a scanning tunneling microscope and a small metal particle [4]. However, from a practical point of view it is obviuos that scanning tunneling microscopes cannot form the basis for any electronics applications where single or complex combinations of SET devices will be used. Lately the focus of possible room temperature SET-devices have instead been shifted towards fabrication of lateral tunnel structures. For instance, Chen et al deposited AuPd nanocrystals between Au electrodes employing combined e-beam lithography and ion beam deposition, and clear Columb blockade effects were observed at 77K [5]. However, the fabrication method is very hard to control and reproduce, which limits it's practical impact from a device point of view. Other proposed techniques that might have a larger potential for device fabrication involves some kind of self- aligning/assembly process(es) of conducting particles between metal electrodes. Such an approach was recently reported by Klein et al. [6] They managed to make a link of several colloidal Au clusters between e-beam defined electrodes. The electrodes were chemically modified in order to promote the adhesion of the colloidal particles. However, this methods lacks controllability in the way the conducting/blocking chain of particles are formed between the electrodes, which also was revealed by large fluctuations in the I-V spectra due to environmental changes during the measurement. In this paper we will, for the first time, report an AFM-based method that besides allowing accurate positioning of individual nanoparticles in the gap between metal electrodes, also allows in-situ 0167-9317(97)/$17.00 © 1997 Elsevier Science B.V~ All tights reserved. PII: S0167-9317(96)00114-1