Bulk Properties of MOCVD-Deposited HfO[sub 2] Layers for High k Dielectric Applications

Abstract

The physical bulk properties of metalorganic chemical vapor deposited (MOCVD) deposited layers were characterized as a function of deposition temperature, thickness, and starting surface. It is shown that depositing layers at 300°C results in a lower density film compared to films deposited at higher temperature (e.g., 485 and 600°C). In addition, it is shown that layers deposited at 300°C contain significant amounts of carbon originating from the organic precursor (tetrakis-diethylamidohafnium). As a result of the low density and/or carbon contamination, the dielectric properties of these layers are very poor. It is observed that the density of the film is heavily dependent on the thickness, where very thin layers have a density that is only a fraction of the bulk density regardless of the deposition temperature. For thicker layers, a higher deposition temperature is seen to result in a higher density, although still lower than bulk density, as observed by ellipsometric porosimetry. Finally, the crystalline state of the material is found to be dependent on the deposition temperature, thickness, and post-deposition anneal. Based on our results, MOCVD deposited layers are expected to be polycrystalline and present in its cubic and/or monoclinic phase. © 2004 The Electrochemical Society. All rights reserved.