Thermal stability of engineered Schottky barriers in Al/Si/GaAs(001) diodes

Schottky barriers as high (low) as 1.0-1.1 eV (0.2-0.3 eV) obtained in Al/n-GaAs(001) diodes by fabricating Si bilayers at the interface under an excess cation (anion) flux were subjected to sequential annealing cycles in the 100-450 degrees C temperature range. X-ray photoemission and current-voltage studies indicate a higher stability for high-barrier diodes, which retain 90% of the Si-induced interface dipole after a 450 degrees C anneal, as compared to only 32% for the low-barrier devices. Qualitatively different microscopic degradation mechanisms were identified in the two cases. (C) 1996 American Institute of Physics.