Optical activation and electrical stabilization of the EL from SiO2:Gd gate oxide layers by fluorine and potassium co-implantations

When amorphous silica is bombarded with energetic ions, various types of defects are created as consequence of ion-solid interaction (oxygen deficient centres ODC, non-bridging oxygen hole centres NBOHC, E’-centres, etc.). Metal-oxide-silicon (MOS) structure contains gadolinium implanted SiO2 layer exhibit strong ultra violet (UV) electroluminescence (EL) at 316 nm from Gd3+ ions and enhancement of luminescence from defects (465 nm, 520 nm and 650 nm corresponds to ODC, Ed’-centre and NBOHC, respectively). Creation and transformation of point defects in bulk SiO2 contains Gd and F atom during constant current injection was investigated. Elimination of such defects is very important from viewpoint of electrical stability of MOS devices. Additional implantation of fluorine in to SiO2:Gd layer leads to decreasing of number of E’-centres and ODC, improves the stability of EL from Gd3+ at 316 nm and lengths working time of MOS structure.