Oxygen partial pressure influenced stoichiometry, structural, electrical, and optical properties of DC reactive sputtered hafnium oxide films

Abstract

HfO2 films have been deposited on quartz and p‐type Si (100) substrates using DC reactive magnetron sputtering technique by sputtering of hafnium target at different oxygen partial pressures. Variation of cathode potential with oxygen partial pressure was systematically studied. The influence of oxygen partial pressure on chemical composition, crystallographic structure, and optical properties of HfO2 films was systematically investigated. X‐ray photoelectron spectroscopy and energy dispersive X‐ray analysis were employed to determine the chemical composition. The films formed at oxygen partial pressure of 5 × 10−4 Torr were of stoichiometric HfO2. X‐ray diffractometer studies revealed that the films formed at 5 × 10−4 Torr were weakly crystallized with monoclinic structure. Optical bandgap of the HfO2 films increased with increasing oxygen partial pressure. Metal oxide semiconductor structures with configuration of Al/HfO2/p‐Si were fabricated and studied its dielectric and electrical properties. From these studies, it is confirmed that HfO2 film‐based metal oxide semiconductor devices formed at an optimum oxygen partial pressure of 5 × 10−5 Torr showed dielectric constant of 13 with leakage current density of 4.7 × 10−7 A/cm2.