Deposition and Electrical Characterization of Very Thin SrTiO3 Films for Ultra Large Scale Integrated Dynamic Random Access Memory Application

Abstract

SrTiO₃ thin films are deposited on Pt/SiO₂/Si substrates using RF magnetron sputtering in a temperature range from 200° C to 600° C. The film deposited at 600° C shows the best dielectric property and leakage current characteristics due to its good crystallinity and stoichiometric composition. Dielectric constant of the film deposited at 600° C decreases with decreasing thickness from 235 at 120 nm to 145 at 30 nm. Leakage current shows a constant value of about 30 nA/cm² at 1.6 V in a thickness range from 50 nm to 120 nm but increases rapidly to 5 µ A/cm² at 30 nm. The electrical properties of the films are explained by a model of the Pt/SrTiO³/Pt capacitor based on the band structure.