Interface Properties Improvement of Ge/Al2O3 and Ge/GeO2/Al2O3 Gate Stacks using Molecular Beam Deposition

Physical and electrical properties of Ge/Al2O3/Pt and Ge/GeO2/Al2O3/Pt gate stacks using molecular beam deposition were proposed in this work. In spite of a straight deposition of Al2O3 on Ge substrate, XPS and TEM analysis revealed the formation of a thin interfacial layer coming from the intermixi...

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Main Authors: Bellenger, Florence, Merckling, Clement, Penaud, Julien, Houssa, Michel, Caymax, Matty, Meuris, Marc, De Meyer, Kristin, Heyns, Marc M.
Format: Conference Proceeding
Language:English
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Summary:Physical and electrical properties of Ge/Al2O3/Pt and Ge/GeO2/Al2O3/Pt gate stacks using molecular beam deposition were proposed in this work. In spite of a straight deposition of Al2O3 on Ge substrate, XPS and TEM analysis revealed the formation of a thin interfacial layer coming from the intermixing between Ge sub-oxides and the high-ĸ dielectric. Electrical measurements showed a high density of interface states (3x1012eV-1.cm-2) mainly due to the presence of this interlayer. Performing a FGA in 10% H2/90% N2 on such structures leads to a significant reduction of DIT and leakage current density. Moreover, growing an in-situ GeO2 layer on Ge before high-ĸ deposition allowed us to reduce the interface states and to reach a very low DIT-value of 1~2x1011eV-1.cm-2 for Ge/GeO2/Al2O3 gate stacks after FGA, providing the efficient passivation of Ge/GeO2 interface. It has also been demonstrated that Al2O3 was a good capping layer, preventing from Ge/GeO2 interfacial degradation under high temperature treatment.
ISSN:1938-5862
1938-6737
DOI:10.1149/1.2981622