C–V characteristics of epitaxial germanium metal–oxide–semiconductor capacitor on GaAs substrate with ALD Al2O3 dielectric

Epitaxial germanium metal–oxide–semiconductor capacitors (MOSCAP) were fabricated on GaAs substrate using atomic layer deposited Al2O3 gate dielectric with surface treatments including pure HF and HF plus rapid thermal oxidation (RTO). The electrical characteristics of 10 nm Al2O3/Ge MOSCAP showed p-type behavior with excellent C–V responses and low leakage current. Interface state density in the order of 1011 eV−1 cm−2 was determined from the conductance method and the HF plus RTO treatment exhibits better Al2O3/Ge interface quality than that of pure HF treatment.

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► Ge film with excellent crystal quality was grown on GaAs substrate by UHVCVD.
► The Ge MOSCAP with HF plus RTO surface treatment performs low Dit value.
► Strong inversion and small frequency dispersion in CV measurement is observed.
► We show great potential for the integration of beyond Si-CMOS logic application.