ON THE RELATIONSHIP BETWEEN INTERFACIAL DEFECTS AND SCHOTTKY-BARRIER HEIGHT IN AG, AU, AND AL N-GAAS CONTACTS/

The variation of the Schottky barrier height in Ag, Au, and Al/n-GaAs contacts has been investigated as a function of the annealing temperat ure of the GaAs substrate. Angle resolved x-ray photoemission spectros copy measurements show that the substrate surface changes from As-rich into Ga-rich over the applied annealing range. Two distinct barrier h eights (about 0.85 and 0.65 eV) are found, depending on the metal and the annealing temperature. These values correspond to the Fermi level pinning positions expected for amphoteric defect reactions involving t he As(Ga) and Ga(As) antisites, respectively. Changes in the barrier h eight are found at annealing temperatures associated with the removal of these defects.