Chemical vapor deposition and characterization of high-k BaHf1−xTixO3 dielectric layers for microelectronic applications

Abstract

Possibilities to grow high-k BaHf1−xTixO3 layers were investigated by pulsed liquid injection metal-organic chemical vapor deposition technique. Ba(thd)2 (thd=2,2,6,6-tetramethylheptane-3,5-dionate), Hf(thd)4, and Ti(OiPr)2(thd)2 were used as precursors, toluene as solvent, and Si(100) as substrate. The influence of solution composition and deposition temperature on crystallization and elemental and phase compositions of Ba–Hf–Ti–O layers was investigated. BaHf1−xTixO3 layers with x∼0–0.5 may be obtained at 600–650 °C, whereas the lower deposition temperature (500–550 °C) resulted in crystallization of the dominating orthorhombic BaCO3 phase in deposited films. Films were characterized by x-ray diffraction, atomic force microscopy, and scanning electron microscopy. Electrical measurements were performed for deposited thin films in view of storage capacitor applications of BaHf1−xTixO3 films in dynamic random access memories.