Interface engineering with pseudormorphic interlayers: Ge metal-insulator-semiconductor structures

Significant improvements in gating of Ge surfaces are achieved with the use of thin, pseudomorphic Si interlayers. Metal-insulator-semiconductor structures with mid-gap interface state densities of 5×1010 cm−2 eV−1 and showing no hysteresis have been realized on both n- and p-type Ge. The key elements of this technology are: surface cleaning, deposition of a thin Si interlayer, and the deposition of the gate dielectric, SiO2, all of which are performed in situ and sequentially at 300 °C in a single chamber with the remote plasma technique. Ion scattering spectroscopy shows complete coverage of the Ge surface by the Si layer. X-ray photoelectron spectroscopy shows the Si interlayer is about 18 Å thick. The Si interlayer prevents the interfacial oxidation of the underlying Ge.