Electroluminescence mechanism in SiO _x layers containing radiative centers

Luminescent silicon oxides containing radiative centers were obtained by using two different techniques. Silicon rich silicon oxides (SRSOs) were fabricated by rf magnetron sputter deposition and Ge-implanted SiO ₂ films were fabricated by ion implantation following the thermal oxidation of Si. Blue and violet photoluminescence were observed from the SRSO and the Ge-implanted SiO ₂, respectively. However, the electroluminescence (EL) spectra from both oxides exhibited red and near-infrared luminescence bands. Strong EL was observed only under reverse bias conditions on metal-luminescent oxide-semiconductor structures. The EL intensity and peak position were varied with applied voltages. According to the EL and current-voltage measurements, it is concluded that the possible EL mechanism is the impact ionization of ground state electrons in the radiative centers.