Improvement of the homogeneity of high mobility In2O3:H films by sputtering through a mesh electrode studied by Monte Carlo simulation and thin film analysis

Abstract

Hydrogen‐doped indium oxide (IOH) is a transparent conductive oxide offering great potential to optoelectronic applications because of its high mobility of over 100 cm2 V−1s−1. In films deposited statically by RF magnetron sputtering, a small area directly opposing the target center with a higher resistivity and lower crystallinity than the rest of the film has been found via hall‐ and XRD‐measurements, which we attribute to plasma damage. In order to investigate the distribution of particle energies during the sputtering process we have simulated the RF‐sputtering deposition process of IOH by particle‐in‐cell Monte Carlo (PICMC) simulation. At the surface of ceramic sputtering targets, negatively charged oxygen ions are created. These ions are accelerated toward the substrate in the plasma sheath with energies up to 150 eV. They damage the growing film and reduce its crystallinity. The influence of a negatively biased mesh inside the sputtering chamber on particle energies and distributions has been simulated and investigated. We found that the mesh decreased the high‐energetic oxygen ion density at the substrate, thus enabling a more homogeneous IOH film growth. The theoretical results have been verified by XRD X‐ray diffractometry (XRD), 4‐point probe, and hall measurements of statically deposited IOH films on glass.