The Dielectric And Tunable Properties Of Mn Doped (ba_(0.6)sr_(0.4))_(0.925)k_(0.075)tio_3 Thin Films Fabricated By Sol-gel Method

摘要

(Ba_(0.6)Sr_(0.4))_(92.5%)K_(7.5%)TiO-3 (BSKT) thin films doped by Mn from 0 to 6 mol % were fabricated by the sol-gel method on a Pt/TiO_2/SiO_2/Si substrate. The structure and surface morphology of Mn-doped BSKT thin films were investigated as a function of Mn concentration by x-ray diffraction and scanning electron microscopy. The dielectric measurements were conducted on metal-insulator-metal capacitors at the frequency from 100 Hz to 1 MHz at room temperature. It was found that the Mn concentration in Mn doped BSKT thin films has a strong influence on material properties including surface morphology and dielectric and tunable properties. Increasing Mn content leads to simultaneous decreasing of surface roughness, dielectric constant, and tunability of Mn doped BSKT films. However the dielectric loss of Mn doped BSKT decreases first and then increases with the increase in Mn dopant. The effects of Mn doping on the microstructure and dielectric and tunable properties of Mn doped BSKT thin films were analyzed. (Ba_(0.6)Sr_(0.4))_(92.5%)K_(7.5%)TiO_3 thin films show the highest dielectric constant and tunability to be 1040 and 73.6%, respectively. However, the 1 mol % Mn doped BSKT thin films with the smallest dielectric loss and upper tunability are the best choice for tunable device applications for its highest figure of merit value of 37.5.