Thermal stability of metal Ohmic contacts in indium gallium zinc oxide transistors using a graphene barrier layer

The excellent impermeability of graphene was exploited to produce stable ohmic contact at the interface between Al metal and a semiconducting indium gallium zinc oxide (IGZO) layer after high-temperature annealing. Thin film transistors (TFTs) were fabricated with and without a graphene interlayer between the Al metal and the IGZO channel region. Metal contact at the interface prepared without a graphene interlayer showed serious instabilities in the IGZO TFT under thermal annealing; however, the insertion of a graphene interlayer between the IGZO channel and the Al metal offered good stability under repeated high-temperature annealing cycles and maintained ohmic contact.