Effects of bombardment of negative oxygen ions on amorphous indium gallium zinc oxide thin films by superimposed rf/dc magnetron sputtering

During the sputtering process, the bombardment effect of negative oxygen ions (NOIs) on the thin-film properties of amorphous indium gallium zinc oxide (a-IGZO) was investigated. The energies of NOIs determined by in situ ion energy analyses are in good agreement with the values obtained using the Meyer equation. Furthermore, we find that the energies of NOIs are sufficiently high to affect the lattice distortion and/or displacement in a-IGZO films. The overall analysis revealed that the bombardment of NOIs has a considerable effect on a-IGZO film properties. Our work demonstrates that the bombardment of NOIs is a crucial issue for achieving high-quality a-IGZO films.