High Performance Atomic-Layer-Deposited \(LaLuO_3/Ge\)-on-Insulator p-Channel Metal-Oxide-Semiconductor Field-Effect Transistor with Thermally Grown \(GeO_2\) as Interfacial Passivation Layer

Abstract

Enhancement-mode p-channel metal-oxide-semiconductor field-effect transistor (MOSFET) on germanium-on-insulator substrate is fabricated with atomic-layer-deposited (ALD) \(LaLuO_3\) as gate dielectric. Significant improvement in both on-state current and effective hole mobility has been observed for devices with thermal \(GeO_2\) passivation. The negative threshold voltage \((V_T)\) shift in devices with \(GeO_2\) 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 \(LaLuO_3\) and ultrathin \(GeO_2\) IL is a promising solution to the tradeoff between the aggressive equivalent oxide thickness scaling and good interface quality.