화학공학소재연구정보센터
Thin Solid Films, Vol.515, No.7-8, 3704-3708, 2007
Electrical properties of Al2O3-HfTiO laminate gate dielectric stacks with an equivalent oxide thickness below 0.8 nm
We report high quality nanolaminate films consisting of five Al2O3-HfTiO layers with a dielectric constant of about 29. The dielectric stack was deposited on unheated p-Si substrate from Al2O3 and 1HfO(2)/1TiO(2) targets using an electron beam gun evaporation system without addition of oxygen. A dielectric constant for a thick HfTiO film of about 83 was also demonstrated. The electrical characteristics of as deposited structures and ones which were annealed for 5-10 min in an O-2 atmosphere at up to 950 degrees C were investigated. Two types of gate electrodes: Pt and Ti were compared. The dielectric stack which was annealed up to 500 degrees C exhibits a leakage current density as small as similar to 1 x 10(-4) A/cm(2) at an electric of field 1.5 MV/cm for a quantum mechanical corrected equivalent oxide thickness of similar to 0.76 nm. These values change to similar to 1 x 10(-8) A/cm(2) and 1.82 nm respectively, after annealing at 950 degrees C for 5 min. (c) 2006 Elsevier B.V. All rights reserved.