High FET Performance for a Future CMOS $\hbox{GeO}_{2}$ -Based Technology

In Germanium-based metal-oxide-semiconductor field-effect transistors, a high-quality interfacial layer prior to high-¿ deposition is required to achieve low interface state densities and prevent Fermi level pinning. In this letter, the physical and electrical properties of a Ge/GeO
₂
/Al
₂
O
₃
gate stack are investigated. The GeO
₂
interlayer grown by radical oxidation and the formation of a germanate (GeAlO
X
) layer at the interface provide a stable high-quality passivation of the Ge channel. High carrier mobilities (235 cm
²
/V·s for electrons and 265 cm
²
/V·s for holes) are demonstrated for a relatively low 3.7-nm equivalent oxide thickness (EOT), enabling the realization of a high-performance CMOS technology with potential EOT scaling.