Impact of film properties of atomic layer deposited HfO2 resulting from annealing with a TiN capping layer

Atomic layer deposited HfO2 films void and exhibit poor electrical characteristics when annealed at high temperature unless a TiN capping layer is used. The TiN is removed prior to characterization of the dielectric. The authors find that capped HfO2 films annealed at 1000°C by rapid thermal process are smooth and void-free. The microstructure of HfO2 is modified from fully monoclinic to a mixed monoclinic and tetragonal phase when the capping layer is used. Conducting atomic force microscopy performed on these films shows fewer areas with high leakage current. Mo∕HfO2 capacitors show improved CV characteristics and lower leakage current density.