ACTA

Properties and Characterization of ALD Grown Dielectric Oxides for MIS Structures

S. Gierałtowska^a, D. Sztenkiel^a, E. Guziewicz^a, M. Godlewski^{a, b}, G. Łuka^a, B.S. Witkowski^a, Ł. Wachnicki^a, E. Łusakowska^a, T. Dietl^{a, c} and M. Sawicki^a
^aInstitute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668 Warszawa, Poland
^bNatural Sciences College of Science, Cardinal S. Wyszyński University, Warszawa, Poland
^cInstitute of Theoretical Physics, University of Warsaw, Warszawa, Poland

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We report on an extensive structural and electrical characterization of under-gate dielectric oxide insulators Al₂O₃ and HfO₂ grown by atomic layer deposition. We elaborate the atomic layer deposition growth window for these oxides, finding that the 40-100 nm thick layers of both oxides exhibit fine surface flatness and required amorphous structure. These layers constitute a base for further metallic gate evaporation to complete the metal-insulator-semiconductor structure. Our best devices survive energizing up to ≈ 3 MV/cm at 77 K with the leakage current staying below the state-of-the-art level of 1 nA. At these conditions the displaced charge corresponds to a change of the sheet carrier density of 3 × 10¹³ cm^-2, which promises an effective modulation of the micromagnetic properties in diluted ferromagnetic semiconductors.

DOI: 10.12693/APhysPolA.119.692
PACS numbers: 81.15.Gh, 77.55.-g, 77.84.Bw, 81.05.Ea