非晶質SrTiO_3薄膜の誘電特性 Dielectric Properties of Amorphous SrTiO_3 Thin Films
In this work, the effects of deposition and annealing conditions on the dielectric properties and dc conductivity were investigated on the thin amorphous SrTiO<SUB>3</SUB> films prepared by a sputtering method using neutralized argon-ion beams. It was demonstrated that the dielectric constant and dc conductivity increased markedly by vacuum annealing and by increasing the target-substrate distance during deposition. The amorphous SrTiO<SUB>3</SUB> films have the optical band gap of about 2.5eV, accompanying with rather wide band tails. This suggests the existence of structural defects which may be caused by oxygen deficiency in the amorphous structure. The amounts of the oxygen deficiency were considered to be dependent on the annealing atmosphere as well as the target-substrate spacing. It is supposed that the ionization of oxygen vacancies, Vo→Vo¨+2e', plays an important role for the dielectric properties and dc conductivity of the amorphous SrTiO<SUB>3</SUB> thin flms. The relative dielectric constants obtained ranged from 20 to 550.
粉体および粉末冶金 43(6), 712-716, 1996-06-15
Japan Society of Powder and Powder Metallurgy