Fully crystallized ultrathin ITO films deposited by sputtering with in-situ electron beam irradiation for touch-sensitive screens

In-situ electron-beam irradiation (EBI) was applied during the sputtering of ITO at room temperature to achieve ultrathin ITO transparent electrodes with low resistivity and high transmittance for applications to the next generation touch-sensitive screens. The resistivity of 30 nm-thick sputtered ITO films and ITO films sputtered with in-situ EBI at room temperature was 7.4×10−4 Ω-cm and 1.5×10−4 Ω-cm, respectively. Hall measurements showed that carrier concentration of ITO films sputtered with in-situ EBI increased by one order of magnitude to 1.7×1021 cm−3 compared to that of the ITO films sputtered without in-situ EBI. Furthermore, the ITO films sputtered with in-situ EBI showed much higher transmittance at the visible wavelength than that of sputtered ITO without EBI due to the Burstein–Moss shift. The significantly low resistivity and high carrier concentration of the ultrathin ITO films produced by sputtering with in-situ EBI can be attributed to the formation of fully crystallized ultrathin ITO films, resulting in the enhanced substitution of Sn4+ to In3+ site through energy transfer from the irradiated electrons to the ad-atoms of ITO during sputtering with in-situ EBI.