Investigation of the properties of PdrGerAurPdrAu ohmic contacts to n-GaAs formed with different ambients

We investigate the effects of different ambients during alloying on the electrical resistance of electron-beam-evaporated PdrGerAurPdrAu contacts to n-GaAs. For an H2rN2ambient, the lowest contact resistivity of 2.1=10y6 V cm2 was obtained after annealing at 4008C for 15 s. For an N2 ambient the lowest contact resistivity of 2.2=10y6 V cm2 was obtained after annealing at 4008C for 45 s. X-ray diffraction, cross-sectional scanning electron microscopy, and Auger electron spectroscopy were utilized in this study. We found that the formation of AuGa and Pd5Ga2 compounds is responsible for the observed low contact resistivity. q1999 Elsevier Science B.V. All rights reserved.