Nitrided HfTiON/Ga2O3(Gd2O3) as stacked gate dielectric for GaAs MOS applications.

GaAs metal–oxide–semiconductor (MOS) capacitors with HfTiON as a gate dielectric and Ga₂O₃(Gd₂O₃) (GGO) as an interlayer annealed in NH₃ or N₂ are fabricated, and their electrical properties are characterized. Experimental results show that the HfTiON/GGO/GaAs MOS device annealed in NH₃ exhibits a low interface-state density (1.1 × 10¹² cm⁻² eV⁻¹), a small gate leakage current (1.66 × 10⁻⁴ A cm⁻² at V_g = V_fb + 1 V), a large equivalent dielectric constant (25.7), and a good capacitance–voltage behavior. All these should be attributed to the fact that the GGO interlayer and postdeposition annealing in NH₃ can effectively suppress the formation of interfacial Ga/As oxides and remove the excess As atoms at the GaAs surface, thus reducing the relevant defects at/near the GGO/GaAs interface. [ABSTRACT FROM AUTHOR]