Current-voltage characteristics of metal-oxide-semiconductor devices containing Ge or Si nanocrystals in thin gate oxides


Current-voltage characteristics of metal-oxide-semiconductor devices containing Ge or Si nanocrystals in thin gate oxides

Beyer, V.; von Borany, J.; Klimenkov, M.; Müller, T.

Current-voltage characteristics were measured, electrically modeled, and calculated for gate oxides, which contain nanocrystals (NCs) in different distributions, sizes, and densities. Ge and Si NCs were synthesized embedded in separate thin SiO2 layers by ion implantation at different fluences and subsequent annealing. It was found that the currents through the NC containing thin gate oxides are strongly related to the NCs’ location and are not driven by ion implantation induced oxide defects. Charging of the NCs determines the internal electrical fields, which is confirmed by simultaneous current and capacitance measurements. Depending on the implanted fluence the Ge NCs were mainly detected in the oxide center or close to the Si/SiO2 interface. The Si NCs were fabricated in the oxide center sandwiched between two oxide regions denuded of NCs. The processes of Si NC formation, growth and dissolution are discussed by means of kinetic lattice Monte Carlo simulations.

Keywords: nanocrystal; Si; Ge; ion implantation; leakage current; kinetic lattice Monte Carlo simulation; memory device

  • Journal of Applied Physics 106(2009), 064505

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