Highly insulative barium zirconate-titanate thin films prepared by rf magnetron sputtering for dynamic random access memory applications

Polycrystalline thin films of Ba(ZrxTi1-x)O-3 With x=0-0.4 and a thickness of similar to 180 nm were deposited on platinum-coated silicon substrates by rf magnetron sputtering at 500 degrees C. Ba-rich targets were used to prepare films of stoichiometric composition. The him having x = 0.12 exhibited a satisfactory dielectric property of dielectric constant, k approximate to 300, and dissipation factor, tan delta<0.02, at frequencies from 10(3) to 10(6) Hz under ambient temperatures ranging from 20 to 180 degrees C. More importantly, the film showed a very stable and highly insulative characteristic against applied voltage. The leakage current density J increases only smoothly to a value less than 10(-7) A/cm(2) followed by an Ohmic relation of J=sigma E with sigma=1.4x10(-14) (Omega cm)(-1) up to an extremely high electric field E of 5.6 MV/cm without any sign of abrupt increase of leakage current or electrical breakdown. Also, no time-dependent electric degradation was observed for the film subjected to an electric field as high as 5 MV/cm at room temperature up to 3600 s of measurement. (C) 1996 American Institute of Physics.