TiO2/Al2O3/TiO2 nanolaminated thin films for DRAM capacitor deposited by plasma-enhanced atomic layer deposition

Abstract

TiO2/Al2O3/TiO2 nanolaminated thin films investigated for the application of dynamic random access memory (DRAM) capacitor dielectrics. TiO2 is a promising high-k material, but its leakage current property is poor. Al2O3 nanolaminated film was inserted between two amorphous TiO2 layers, and an Al2O3 thickness greater than 10 effectively reduced the leakage current. When TiO2 layers were crystallized to enhance the dielectric constant, a thicker Al2O3 sublayer was required. As a result, anatase-TiO2(40 angstrom)/Al2O3(12.5 angstrom)/rutile-TiO2(40 angstrom) nanolaminated film is suggested as an optimal structure that gives k = 44 (equivalent oxide thickness ) with a leakage current of 6.46 x 10(-7) A/cm(2) at 1 MV/cm. (c) 2007 The Electrochemical Society.