Thermally stable PtSi Schottky contact on n-GaN

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 degrees 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 degrees C. Upon annealing at 600 degrees 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 degrees C for 1h, the Pt diodes degraded and most of the diodes did not survive additional annealing at 400 degrees 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. (C) 1997 American Institute of Physics.