Paper EM-ThP7
Preparation and Characterization of HfO₂ Thin Films Prepared by Atomic Layer Deposition on Silicon

Thursday, October 18, 2007, 5:30 pm, Room 4C

In recent years, the continuous downward scaling of dynamic random access memory capacitors, requires exploitation of capacitive devices of advanced topology, i.e. stacked or trenched structures. In choosing the replacement high-k materials for SiO₂ for the transistor gate region several challenging factors should be taken into account such as: a) the dielectric-silicon interface quality and stability b) the relation between the dielectric constant and the energy level configurations (energy band gap) c) energy band offsets, which could lead to an increase in the leakage current d) defect density at the interface. Among the many possible candidate high-k (15-30) dielectric materials, HfO₂emerging as a promising gate dielectric material, due to its high dielectric constant and superior thermal stability on Si substrates. Moreover, the ALD (atomic layer deposition) method is preferred for obtaining these high quality high-k dielectric layers, because of its excellent thickness controllability and low thermal budget. In the present study, HfO₂ thin films were atomic layer deposited from the liquid hafnium precursor TEMA (Hf[N(CH₃)(C₂H₅)] ₄) precursor and O₃ oxidation and were characterized using angle resolved X-ray photoelectron spectroscopy , scanning transmission electron micrscopy , and electron energy loss spectroscopy .