Improvement of Properties of SrTiO3 Thin Films Deposited at Low Temperature and High Rate by Sputtering Gas

Abstract

SrTiO3 thin films have been prepared by RF magnetron sputtering at a low substrate temperature of 200°C and a high deposition rate of 35 nm/min on Al/glass substrates. X-ray diffraction data indicated that deposited SrTiO3 thin films were partially polycrystalline and/or amorphous. The properties of SrTiO3 thin films were improved by sputtering gas. As the mass of the sputtering gas was light, the signal intensity ratios of Ti/Sr in the optical emission spectra increased, and surface protrusions were suppressed. In particular, in the presence of N2 gas, the properties of SrTiO3 films were improved, and the leakage current density and tan δ markedly decreased. SrTiO3 film of 300 nm thickness exhibited the dielectric properties with a relative dielectric constant of 62 and a leakage current of 4×10-10 A/cm2 at a voltage of +5 V, and tan δ of 0.6% at 1 kHz.