The annealing effect of Schottky contact on AlGaN/GaN

The AlGaN/GaN samples were grown on sapphire substrates by MOCVD. A Ti/Al/Ti/Au multi-layer film and Ni/Au bi-layer film were sputtered for ohmic contact and Schottky contact respectively. The optimal annealing temperature of the Schottky contact was determined as 450/spl deg/C. The ideality factor and Schottky barrier height were calculated out from the I-V curves of the Schottky contact. One fitting formula for the leakage current of the Schottky contact was set up and its parameters dependence on the annealing temperature were discussed. The parameter A was linear with the negative SBH, and the parameter B was related to the GaN material intrinsic factors.