Radiation induced trap levels in SIMOX oxides: low temperature thermally stimulated luminescence

Thermally Stimulated Luminescence (TSL) properties of SIMOX oxides, induced by x-irradiation, have been studied in the temperature range 100-400 K. For the first time studied in SIMOX, a series of TSL peaks at 110, 150 and 200 K appear clearly. A continuous distribution of trap levels ranging from 0.4 to 1.1 eV has been found to be responsible for the broad and intense peak observed at 200 K; moreover, the wavelength distribution of the emitted light has revealed the presence of an emission centred at 2.7 eV. A comparison with the TSL properties of synthetic silica is presented, and the results are discussed also in the light of previous characterizations of trap levels obtained by electrical techniques. This study gives new insight concerning the electron and hole traps structures in SIMOX compared to bulk silica.