SURFACE-CHARGE PROPERTIES OF FLUORINE-DOPED LEAD BOROSILICATE GLASS

Surface-charge configurations, together with stability under bias-temperature (BT) stress, for F-doped and Na-doped lead borosilicate glass were investigated by using C-V and I-V measurements on metal-glass-silicon capacitors and on diodes passivated with the glass. The C-V characteristics showed an increase in negative charge for F doping and in positive charge for Na doping. Alkali impurities in the glass mainly controlled the surface-charge shift during BT, but additional changes, similar to those for Na doping but reversing the sign of the charge, took place by F doping. The leakage current decrease in the diode passivated with F-doped glass, which contradicts the results of C-V measurement, may be due to the reduction of the generation current by the interaction between the silicon surface and F**- ions.