Oxides with Thin Metallic Layers as Transparent Ohmic Contacts for P-Type and N-Type Gallium Nitride

摘要

Transparent conductive layers usable as ohmic contacts for III-V semiconductors with work functions between 4.1 and 4.7 eV are formed by annealing layers of transparent oxide with thin (0.1-5 nm) layers of conductive metal. When the layers interdiffuse during the annealing, some of the conductive metal atoms remain free to reduce resistivity and others oxidize to reduce optical absorption. Examples of the transparent oxides include indium-tin oxide, zinc oxide, and aluminum zinc oxide with up to 5 wt % Al. Examples of the metals include aluminum and titanium. The work function of the transparent conductive layer can be tuned to match the contacted semiconductor by adjusting the ratio of metal to transparent oxide.