Al/Si/AlGaAs/GaAs Schottky barriers by molecular beam epitaxy

Abstract

We have grown Al/Si/AlGaAs/GaAs Schottky diode structures by molecular beam epitaxy utilizing thin Si (6 Å) and AlxGa1−xAs (1500 Å) interfacial layers with Al mole fractions of x=0, 0.15, and 0.30. The compositional dependence of the Schottky barrier height, as determined by I-V measurement, is equal to that of the conduction band discontinuity between AlGaAs and GaAs. The barrier heights as determined by C-V, however, show no compositional dependence. Since the C-V characteristics depend only on the difference in the conduction band discontinuities for the Si-AlGaAs and GaAs-AlGaAs heterojunctions, this suggests that the change in conduction band discontinuity due to Al mole fraction is the same for both heterojunctions for the range of x studied.