HfO 2 gate dielectrics deposited VIA Tetrakis Diethylamido Hafnium

Abstract

HfO 2 films deposited via Tetrakis Diethylaraido Hafnium (TDEAH) precursor using MOCVD (Metal Organic Chemical Vapor Deposition) are presented. TDEAH is a promising precursor candidate for the deposition of high permittivity gate dielectrics. We report the impact of process and annealing conditions on the physical and electrical properties of the film. Deposition and annealing temperatures influence the microstructure, density, and impurity levels of TDEAH HfO 2 films. Spectroscopic ellipsometry shows that film microstructure manifests itself in the optical properties of the film, particularly in the presence of a band edge related feature at 5.8eV. An impurity analysis using Auger Electron Spectroscopy, Secondary Ion Mass Spectroscoy, and Raman Spectroscopy, indicates that carbon impurities from the precursor exist as clusters within the HfO 2 dielectric. The impact of deposition temperature and annealing temperature on the Capacitance vs. Voltage and Current Density vs. Voltage characteristics of platinum gated capacitors is studied. Correlation of physical film properties with the capacitance and leakage behavior of the TDEAH HfO 2 films indicates that impurities, in the form of carbon clusters, and low HfO 2 film density are detrimental to the electrical performance of the gate dielectric.