Low-resistance Ti/Au ohmic contacts to Al-doped ZnO layers

Abstract
We report on low-resistance ohmic contacts to the moderately doped n-type ZnO:Al(nd=2×1017 cm−3) obtained using Ti (30 nm)/Au (50 nm) metallization schemes. Annealed Ti/Au contacts exhibit linear current–voltage characteristics, showing that high-quality ohmic contacts are formed. The Ti/Au scheme produces a specific contact resistance of 2×10−4 Ω cm2 when annealed at 300 °C for 1 min in a N2 atmosphere.