Nonalloyed Al ohmic contacts to Mg^sub x^Zn^sub 1-x^O

Al nonalloyed ohmic contacts were fabricated and characterized on Mg^sub x^Zn^sub 1-x^O (0≤×≤0.34) epilayers, which were grown on R-plane sapphire substrates by metal organic chemical vapor deposition (MOCVD). Specific contact resistances were evaluated by the transmission line method (TLM). A specific contact resistance of 2.5×10^sup -5^ Ωcm^sup 2^ was obtained for Al contact to ZnO with an electron concentration of 1.6×10^sup 17^ cm^sup -3^. The current flow mechanism was studied by investigating the dependence of specific contact resistances on electron concentration and on temperature. For Al contact to Mg^sub 0.34^Zn^sub 0.66^O, specific contact resistance values are two orders of magnitude larger than that of Al ohmic contacts to ZnO.[PUBLICATION ABSTRACT]