Crystallinity Effect on Electrical Properties of PEALD-HfO 2 Thin Films Prepared by Different Substrate Temperatures.

Hafnium oxide (HfO 2 ) thin film has remarkable physical and chemical properties, which makes it useful for a variety of applications. In this work, HfO 2 films were prepared on silicon through plasma enhanced atomic layer deposition (PEALD) at various substrate temperatures. The growth per cycle, structural, morphology and crystalline properties of HfO 2 films were measured by spectroscopic ellipsometer, grazing-incidence X-ray diffraction (GIXRD), X-ray reflectivity (XRR), field-emission scanning electron microscopy, atomic force microscopy and x-ray photoelectron spectroscopy. The substrate temperature dependent electrical properties of PEALD-HfO 2 films were obtained by capacitance-voltage and current-voltage measurements. GIXRD patterns and XRR investigations show that increasing the substrate temperature improved the crystallinity and density of HfO 2 films. The crystallinity of HfO 2 films has a major effect on electrical properties of the films. HfO 2 thin film deposited at 300 °C possesses the highest dielectric constant and breakdown electric field.