Potential barrier formation at a metal-semiconductor contact using selective removal of atoms

Abstract

The possibility of forming a potential profile in a semiconductor by forming a metal film on its surface via selective removal of oxygen atoms from a deposited metal oxide layer was studied. Selective removal of atoms (SRA) was performed using a beam of accelerated protons with an energy of about 1 keV. Epitaxially grown GaAs films with a thickness of ∼100 nm and an electron concentration of 2×10¹⁷ cm⁻³ were chosen as the semiconductor material, and W obtained from WO₃ was used as the metal. The potential profile appeared due to the formation of a Schottky barrier at the metal-semiconductor interface. It was found that the Schottky barrier formed at W/GaAs contacts made by the SRA method is noticeably higher (∼1 eV) than the barrier formed at the contacts made by conventional metal deposition (0.8 eV for W/GaAs). The data presented indicate that there is no damaged layer in the gate region of the structures, which is most strongly affected by the proton irradiation. Specifically, it was shown that the electron mobility in this region equals the mobility in bulk GaAs with the same doping level.