Effects of Ultrathin TiO_x Seeding Layer on Crystalline Orientation and Electrical Properties of Sputtered (Ba,Sr)TiO_3 Thin Films

摘要

A series of ultrathin TiO_x (0-12 nm) seeded (Ba,Sr)TiO_3 (BST) thin films have been prepared on Pt (111)/TiO_x/SiO_2/Si substrates by RF-magnetron sputtering. Experimental results show that an ultrathin TiO_x layer acts as an initial template for the BST films in the first nucleation stage, resulting in a significant influence on crystalline orientation and electrical characteristics of the resultant BST films. Interestingly, highly (111) oriented BST film [α(111) ～ 97%] with 5-nm-thick TiO_x seeding layer exhibits a shifted Curie temperature (T_c = 275 K) and an enhanced tunability of 61.16% at 400 kV/cm, when compared with (001)-oriented BST without TiO_x layer (T_c = 250 K and tunability = 50.05%).