SOI-Based Silicon Quantum Dots Contacted by Self-Aligned Nano-Electrodes

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ABSTRACTIn this paper we present a novel approach to fabricate single-electron devices utilizing different self-organization and self-alignment effects. Silicon quantum dots (QDs) are obtained employing reactive ion etching (RIE) into a silicon-on-insulator (SOI) substrate with a self-assembled etch mask. Electrodes with nanometer separation are fabricated and aligned to the QDs by means of a controlled electromigration process. The tunneling rates of the devices are defined by the native oxide covering the silicon QDs and can be adjusted by self-limiting thermal oxidation. The devices show clear Coulomb blockade behavior as well as Coulomb staircase features. In some samples also a gate influence is present giving rise to Coulomb diamonds in the differential conductance diagram.