Multiplet luminescence of sulfur implanted silica - SiO2 : S

Thermally wet oxidized SiO2 layers of 500 nm thickness have been implanted by sulfur ions of energy 150 keV and a dose 5 x 10(16) ions/cm(2) leading to an atomic dopant fraction of 4 at% at a mean depth of 190 nm. The cathodoluminescence spectra of these sulfur implanted SiO2 layers show besides a characteristic violet band at 405 nm a sharp and intensive multiplet structure beginning in the green region at 500 nm over the yellow-red region and extending to the near IR measured up to 820 nm. The energy step differences of the sublevels amount in average to 120 meV and indicate vibration associated electronic states, probably, of unsaturated sulfur radicals equivalent to Si-S center dot or equivalent to Si-O-S center dot substituting the former nonbridging oxygen hole center (NBOHC) equivalent to Si-O center dot as an intrinsic defect of the pure SiO2. After 1 min electron beam irradiation with a dose of 0.3 As/cm(2) the spectral multiplet structure is nearly lost but the NBO! HC red band R (660 nm) remains.