MODIFICATION OF AL GAAS(001) SCHOTTKY BARRIERS BY MEANS OF HETEROVALENT INTERFACE LAYERS/

The Schottky barrier height in Al/Si/Ga-As(001) junctions grown by mol ecular-beam epitaxy was determined in situ by means of x-ray photoemis sion spectroscopy and ex situ through current-voltage and capacitance- voltage measurements. We found that the barrier height can be tuned fr om a minimum value of 0.2 eV to a maximum of 1.1 eV provided that a su fficiently high As or Al flux is employed during the growth of the Si interface layer. The minimum and maximum values of the barrier are alr eady established for Si layer thicknesses in the 1-2 monolayer range. We propose that the changes in barrier height derive from the establis hment of a Si-induced local interface dipole. The magnitude and orient ation of the dipole reflects the detail of the atomic reconstruction a chieved at the interface in the different growth conditions.