Optimization of the deposition technique of thin ITO films used as transparent conducting contacts for blue and near-UV LEDs

Structural, optical, and electrical properties of indium-tin oxide (ITO) films produced by electron-beam evaporation, magnetron sputtering, and a combined method are studied. It is demonstrated that, despite the high transparency of the electron-beam-deposited ITO films in the visible spectral range, their conductivity and refractive index are noticeably lower than the respective parameters of ITO films deposited by magnetron sputtering. A technique for the fabrication of double-layer systems by the combination of these two deposition techniques is developed. As a result, we obtained the films, which possess the advantages of magnetron-sputtered layers and can be used as contact layers to $p$-type GaN in LEDs for the blue and nearultraviolet (near-UV) spectral ranges.