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

Hafnium oxide (HfO) thin film has remarkable physical and chemical properties, which makes it useful for a variety of applications. In this work, HfO 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 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 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 films. The crystallinity of HfO films has a major effect on electrical properties of the films. HfO thin film deposited at 300 °C possesses the highest dielectric constant and breakdown electric field.