Ultralow Resistance Si-containing Ti∕Al∕Mo∕Au Ohmic Contacts with Large Processing Window for AlGaN∕GaN Heterostructures

We report on the electrical and microstructural characterization of Si-containing Ti∕Al∕Mo∕Au contacts for AlGaN∕GaN heterostructures. Excellent Ohmic contact formation with contact resistance and specific contact resistivity as low as 0.12Ωmm and 3.8×10−7Ωcm2, respectively, have been obtained by the optimization of Si distribution in the metallization. The presence of Si strongly affects the Ohmic performance and microstructural makeup of the annealed contacts. Greater enhancement in Ohmic performance is achieved when optimized amount of Si is dispersed throughout the metallization.