Thermally stable PtSi Schottky contact on n-GaN

Platinum suicide (PtSi) and Pt Schottky contacts on n-GaN have been investigated and compared. The PtSi contacts were formed on n-GaN by annealing a multilayer structure of Pt/Si with the appropriate thickness ratio at 400°C for 1 h in forming gas. The barrier height of the as-formed PtSi contacts was found to be 0.87 eV capacitance-voltage (C-V), and remained unchanged after further annealing at 400 and 500°C. Upon annealing at 600°C for 1 h, the barrier height decreased to 0.74 eV (C-V), but the diodes remained well-behaved. The as-deposited Pt yielded a barrier height of 1.0 eV (C-V). Upon annealing at 400°C for 1 h, the Pt diodes degraded and most of the diodes did not survive additional annealing at 400°C for longer times. The electrical measurements and the Rutherford backscattering spectrometry results indicated that PtSi contacts are thermally much more stable than Pt contacts on GaN.