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

Abstract

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 ( $3.4 \times 10^{11}$ cm $^{-2}$ eV $^{-1}$ ), small gate leakage current ( $2.93 \times 10^{-5}$ A/cm2 at $V_{g} = V_{\mathrm{fb}} + 1$ 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 GeO x interfacial layer.