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

Abstract

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 (1.24×1012cm−2eV−1 near midgap), smaller gate leakage current density (1.34×10−5A/cm2 at Vfb+1V), smaller capacitance equivalent thickness (1.43nm), 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.