Contact Resistivity and Adhesion of Ni/AuGe/Ag/Au Ohmic Contact Directly to n-Type AlGaAs

Abstract
The direct ohmic contact to AlGaAs, Ni/AuGe/Ag/Au=5/120/100/580 nm has been studied. Contact resistivity of 3.8×10-5 Ω cm2 is obtained after thermal treatment for 10 min at 450° C. This is one order lower than that of the conventional Ni-Ge-Au system. The new metallization also indicates strong adhesion on SiN x film, does not peel off even after thermal treatment during all device processes and withstands the wire bonding process. We conclude that the metallization is useful and applicable for AlGaAs-related devices.