Dielectric and leakage current characteristics of Ba(Ti1-xZrx)O-3 thin films deposited by rf magnetron sputtering

Cubic perovskite Ba(Ti1-xZrx)O-3 (BTZ) thin films of x = 0.12 and 150-180 n m thick were prepared on Pt/Ti/SiO2/Si substrate by rf magnetron sputtering deposition at high temperatures. A satisfactory dielectric constant of 250 -305 was obtained for the films deposited at 400 degrees C and 500 degrees C, respectively, but reduced to 210 for that deposited at 600 degrees C. Th e two films deposited at lower temperatures also had a lower reduction of c apacitance against biasing voltage than that at 600 degrees C, and, more im portantly, the two exhibited a high and very stable insulating characterist ics against biasing. A low leakage current density less than 3 x 10(-9) A/c m(2) was maintained up to a high biasing voltage of 1-2 MV/cm before the on set of an abrupt non-ohmic emission for the two films in a Pt/BTZ/Pt capaci tor configuration, and no time-dependent degradation of electric resistance was observed for the two films subjected to a field as high as 2 MV/cm at room temperature. Moreover, a tunneling-like current relation was also foun d for the non-ohmic current emission in the 500 degrees C-deposited BTZ spe cimen measured at temperatures ranging from room temperature to 420K. Howev er, the leakage current characteristic of the 600 degrees C-deposited film was greatly degraded. (C) 1998 Published by Elsevier Science S.A. All right s reserved.