Comparison of Mocvd Precursors for Hf1-xSixO2 Gate Dielectric Deposition

Abstract

AbstractThis study investigates and compares the deposition of Hf1-xSixO2 films from two suites of metalorganic CVD precursors. The first precursor suite has oxygen coordinated to the Si or Hf center and includes β-diketonate, alcoxide and acetoxy ligands. The second precursor suite has alkylamido ligands, which have nitrogen coordinated to the Hf or Si center. The process space for deposition of silicates was evaluated for controlling the composition of the silicate films while optimizing deposition rates for a manufacturable single-wafer process. The composition of the film, x, is controlled over the entire range by changing the composition of the precursor solution, Si:Si+Hf. The composition of the films, including hafnium, silicon, oxygen, carbon, and nitrogen content were measured by XPS. Both suites of precursors provide routes by which composition can be controlled in fully oxidized films with low carbon and nitrogen content. Film deposition rates are consistent with manufacturing requirements. The interfacial layers that were observed by HRTEM between the film and the substrate were thin (< 10Å) and possibly graded in composition.