Ohmic Contacts to Gallium Nitride-Based Structures

Studies of the characteristics of ohmic contacts to epitaxial and ion-doped gallium-nitride layers, based on the Cr/Pt/Au metallization system, are reported. The possibility of forming low-resistance contacts without the application of high-temperature treatment is shown. It is demonstrated, for AlGaN/GaN-based heterostructures, that the characteristics of Ti/Al/Ni/Au ohmic contacts are improved upon using ion implantation through a silicon-dioxide mask.