Optical and electrical characterization of hafnium oxide deposited by liquid injection atomic layer deposition

Optical and electrical properties of a set of high-k dielectric HfO2 films, deposited by liquid injection atomic layer deposition (LI-ALD) and post deposition annealed (PDA) in nitrogen (N2) ambient at various temperatures (400–600 °C), were investigated. The films were prepared using the cyclopentadienyl of hafnium precursor [Cp2Hf(CH3)2] with water deposited at 340 °C. The spectroscopic ellipsometric (SE) results show that the characteristics of the dielectric functions of these films are strongly affected by annealing temperatures. I–V results show that N2-based PDA enhances the average energy depth of the shallow trapping defects from Poole–Frenkel conduction fitting. This also correlated with the measured increase in MOS capacitance–voltage hysteresis.