Schottky barrier height dependence on the silicon interlayer thickness of Au\Si\-GaAs contacts : chemistry of interface formation study

This work reports on the X-ray photoemission spectroscopy (XPS) measurements of the As-rich GaAs(001) surface properties developing due to the different thicknesses of the undoped silicon overlayers. We analyzed the bond nature on the silicon–GaAs interface depending on the silicon thickness which was connected with observed variations in surface Fermi level positions. Further, the Au\Si\-GaAs metal-semiconductor contacts were prepared on the studied structures. Measured changes in the Schottky barrier height for silicon thicknesses till approximately 1 nm are interpreted through the approach of the Schottky barrier height to Schottky limit due to decrease of the interface state densities on the Si\GaAs interface.