Hydrogen radical enhanced atomic layer deposition of TaOx: saturation studies and methods for oxygen deficiency controlElectronic supplementary information (ESI) available. See DOI: 10.1039/c8tc00679b

The growth per cycle saturation behaviors depending on the precursor pulse duration, reactant pulse duration, and reactant concentration were examined for hydrogen radical enhanced atomic layer deposition (REALD) of TaO x using tantalum-ethoxide as the precursor and plasma-activated hydrogen as the reactant. The chemical state of the TaO x film was dependent on the active hydrogen pulse duration and hydrogen volume fraction in the H 2 /Ar plasma mixture. The density of the electronic states in the dielectric band gap increased with the increase in the plasma exposure time (6-50 s) and hydrogen volume fraction (7-70%) whereas Ta4f core-level X-ray photoelectron spectroscopy indicated that the observed defects in the TaO x band gap are related to the oxygen deficiency. The ab initio calculations of oxygen deficiency concentrations and the energy spectrum satisfactorily correlated with the experimental data. The demonstrated combination of the growth saturation availability with the precise control of oxygen deficiency concentrations in the PEALD process could be highly useful in fields in which oxide dielectrics with adjustable oxygen deficiencies are required. Investigations of saturation behaviors of growth rate and valence band states in TaO x (tantalumethoxide and plasma-activated hydrogen) ALD process.