THERMALLY STABLE PTSI SCHOTTKY CONTACT ON N-GAN

Platinum silicide (PtSi) and Pt Schottky contacts on n-GaN have been i nvestigated and compared. The PtSi contacts were formed on n-GaN by an nealing 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-voltag e (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 heigh t decreased to 0.74 eV (C-V), but the diodes remained well-behaved. Th e as-deposited Pt yielded a barrier height of 1.0 eV (C-V). Upon annea ling at 400 degrees C for 1h, the Pt diodes degraded and most of the d iodes 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 m ore stable than Pt contacts on GaN. (C) 1997 American Institute of Phy sics.