In₂O₃-based Transparent Conductive Oxide Films with High Electron Mobility

Abstract

We have investigated the effects of dopants (Ti, Zr, H, Sn) and growth processes for In₂O₃ transparent oxide films in terms of their electrical and optical properties. Ti- and Zr-doped In₂O₃ showed higher mobility than conventional Sn-doped In₂O₃ in epitaxial and polycrystalline films fabricated by vapor-phase-crystal growth. On the other hand, we have found that polycrystalline H-doped In₂O₃ films fabricated by crystallization of the amorphous phase at 200^oC show larger mobility (130 cm²/Vs) with resistivity of 2.7×10⁻⁴ Ωcm and improved near infrared transparency. Analysis of temperature dependence of Hall mobility reveals that the high mobility in the H-doped In₂O₃ films is ascribable to suppression of multicharged and neutral impurities as well as grain boundary defects. Relationship between the values of room temperature Hall mobility and carrier concentration further supports our conclusion.