N₂-Plasma-Treated Ga₂O₃(Gd₂O₃) as Interface Passivation Layer for Ge MOS Capacitor with HfTiON Gate Dielectric

The interfacial and electrical properties of sputtered Ti-incorporated Hf oxynitride on Ga2O3(Gd2O3) (GGO) with or without N2-plasma treated as an interfacial passivation layer (IPL) for Ge MOS capacitor are compared. It is found that low interface-state density (3.4 × 1011cm-2eV-1), small gate leakage current (2.93 × 10-5A/cm2at Vg= Vfb+ 1 V), small capacitance equivalent thickness (1.09 nm), and large equivalent dielectric constant (26.5) can be achieved for the sample with N2-plasma-treated GGO IPL. The involved mechanisms lie in the fact that the N2-plasma-treated GGO IPL can effectively block the interdiffusion of elements and suppress the formation of GeOxinterfacial layer.