Study of Deep Bulk Traps of Low-Temperature-Sintered SrTiO_3 GBBL Capacitors

A deep bulk trap level of SrTiO3 grain boundary barrier laper (GBBL) capacitor material was found to be at about 0.21eV below its conduction band by means of admittance spectroscopy. With temperature increasing from --150 to 10℃, the eeff protrusion and then the conspicuous dispersity of dielectric constant were observed and explained. In terms of a combination of paraelectric behaviour of SrTiO3 and a deep bulk trap effect, an equivalent circuit model involving the deep bulk level was given. Based on the model, a reasonable cosistency of calculated dielctric constants with experimental data was revealed.