High performance atomic-layer-deposited LaLuO₃ /Ge -on-insulator p-channel metal-oxide-semiconductor field-effect transistor with thermally grown GeO₂ as interfacial passivation layer

Enhancement-mode p-channel metal-oxide-semiconductor field-effect transistor (MOSFET) on germanium-on-insulator substrate is fabricated with atomic-layer-deposited (ALD) LaLuO₃ as gate dielectric. Significant improvement in both on-state current and effective hole mobility has been observed for devices with thermal GeO₂ passivation. The negative threshold voltage (V_T) shift in devices with _GeO2 interfacial layer (IL) further demonstrates the effectiveness of surface passivation. Results from low temperature mobility characterization show that phonon scattering is the dominant scattering mechanism at a large inversion charge, indicating good interface quality. The combination of higher- k LaLuO₃ and ultrathin GeO₂ IL is a promising solution to the tradeoff between the aggressive equivalent oxide thickness scaling and good interface quality.