Improved interfacial quality of GaAs metal-oxide-semiconductor device with NH3-plasma treated yittrium-oxynitride as interfacial passivation layer

•Using yittrium-oxynitride as interfacial passivation layer to get a good interface•Using NH3 or N2 plasma to treat YON interfacial passivation layer and passivate the interface•The sample treated by NH3 plasma shows better performance.

The interfacial and electrical properties of GaAs metal-oxide-semiconductor capacitors with yittrium-oxynitride interfacial passivation layer treated by N2 −/NH3-plasma are investigated, showing that lower interface-state density (1.24 × 1012 cm− 2 eV− 1 near midgap), smaller gate leakage current density (1.34 × 10− 5 A/cm2 at Vfb + 1 V), smaller capacitance equivalent thickness (1.43 nm), and larger equivalent dielectric constant (24.5) can be achieved for the sample with NH3-plasma treatment than the samples with N2 −/no-plasma treatment. The mechanisms lie in the fact that NH3-plasma can provide not only N atoms, but H atoms and NH radicals to effectively passivate the high-k/GaAs interface, thus less pinning the Femi level at high-k/GaAs interface.