Si Quantum Dots for Single Electron Transistor: Synthesis, Characterization and Theoretical Comparison

The appearance of quantum effects makes nanoparticles (NPs) more and more important in semiconductor physics and especially in nanoelectronics. One very promising application is the single electron transistor (SET). Common field effect transistors (FET) could be outperformed by SETs in many applications because of their ultra-low power consumption (~100 times). Important for the fabrication of SETs operating at room temperature is the control of position and size of nano dots (<5nm). Our CMOS-compatible approach to manufacture SETs follows a two-step synthesis of NPs: (i) Producing tiny SiOx volumes by ion beam irradiation of ultrathin buried SiO2 layers (<10nm) and (ii) self-organizing single Si nanodots by phase separation during thermal treatment.
Energy-filtered transmission electron microscopy (EFTEM) is an advanced technique for the structural analysis of Si NPs in buried SiO2 layers. Although the NPs in the SiO2 layer superimpose in 2-dimentional projections from cross-sectional TEM samples, we managed to characterize the density and size distribution of the formed nanoclusters using the knowledge of the electron mean free path length to convert the Si-plasmon-loss filtered TEM image into a Si-thickness map. Here we will present the characterization and a comparison with theory to show a significant overestimation of the mixing effect by BCA simulation. This work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 688072.