Effects of substrates on the structure and dielectric properties of Ba(Sn0.15Ti0.85)O3 thin films

Ba(Sn0.15Ti0.85)O3 (BTS) thin films were grown on Pt(1 1 1)/Ti/SiO2/Si and LaNiO3(LNO)/Pt(1 1 1)/Ti/SiO2/Si substrates by a sol–gel processing technique, respectively. The BTS thin films deposited on annealed Pt(1 1 1)/Ti/SiO2/Si and annealed LNO/Pt(1 1 1)/Ti/SiO2/Si substrates exhibited strong (1 1 1) and perfect (1 0 0) orientations, respectively. The BTS thin films grown on un-annealed Pt(1 1 1)/Ti/SiO2/Si substrates showed random orientation with intense (1 1 0) peak, while the films deposited on un-annealed LNO/Pt(1 1 1)/Ti/SiO2/Si substrate exhibited random orientation with intense (1 0 0) peak, respectively. The dielectric constant of the BTS films deposited on annealed Pt(1 1 1)/Ti/SiO2/Si, annealed LNO/Pt(1 1 1)/Ti/SiO2/Si, un-annealed Pt(1 1 1)/Ti/SiO2/Si and un-annealed LNO/Pt(1 1 1)/Ti/SiO2/Si substrates was 512, 565, 386 and 437, respectively, measured at a frequency of 100 kHz. A high tunability of 49.7% was obtained for the films deposited on annealed LNO/Pt(1 1 1)/Ti/SiO2/Si substrate, measured at the frequency of 100 kHz with an applied electric field of 200 kV/cm. The high tunability has been attributed to the (1 0 0) texture of the films and larger grain sizes.