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. (C) 2010 American Institute of Physics. [doi:10.1063/1.3462303]