Platinum silicide (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℃ 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 ℃. Upon annealing at 600 ℃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 ℃for 1 h, the Pt diodes degraded and most of the diodes did not survive additional annealing at 400 ℃ 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. # 1997 American Institute of Physics.S0003-6951(97)01110-8
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