Charge storage properties and electroluminescence in silicon nanocrystals fabricated by ion beam mixing of gate oxide/silicon interfaces

The present contribution addresses the Si nanocrystal formation by a non-conventional ion beam synthesis approach of ion beam mixing of SiO2/Si interfaces in thin gate oxides, with special emphasis on well-controlled size and position tailoring as well as on their application in non-volatile nanocrystal memories and in light emitting field-effect transistors. The Si nanocrystal MOSFETs were fabricated as nMOSFET devices and their electrical characteristics have been evaluated in terms of write/erase voltage, duration of the programming time, endurance and retention for different ion irradiation and annealing conditions. For the investigation of the light emitting characteristics of the same nMOSFETs an AC voltage was applied to the gate in order to inject charges of both polarities into the nanocrystals leading to the formation of excitons there. They recombine under emission of a photon, whereas the emitted wavelength is a function of the nanocrystal size. AC voltage and frequency dependent electroluminescence spectra in the wavelength region of 400-1000 nm were recorded for different annealing conditions.