Growth of Hafnium Aluminate Thin Films by Direct Liquid Injection Metallorganic CVD Using Hf [ N ( C 2 H 5 ) 2 ] 4 and Al ( O i C 3 H 7 ) 3

Abstract

A mixtured solution of (tetrakis-diethylamido-hafnium, TDEAH) and (aluminum iso-propoxide) dissolved in n-octane was used in the direct liquid injection metallorganic chemical vapor deposition (DLI-MOCVD) for the deposition of hafnium aluminate thin films. The effect of the deposition temperature and the concentration of the precursors in the solution on the deposition rate and the composition of the hafnium aluminate film were studied in the deposition temperature range of 200-475°C. The deposition rate was increased up to the deposition temperature of 350°C with the activation energy of about 3.6 kcal/mol and then decreased due to the gas-phase dissociation of the precursor. The incorporation of aluminum into the film depends almost linearly on the concentration of the aluminum precursor in the solution. As the Al incorporation in the film was increased, crystallization temperature of the film was increased, but the grain size measured by scanning electron microscope was not significantly changed with the increase of the annealing temperature. For 100 nm thin film, the dielectric constant and the leakage current density of Hf aluminate film (about 65% aluminum phase) annealed at 800°C was 11.1 and A/cm2 at 5 V, respectively. © 2005 The Electrochemical Society. All rights reserved.