title: Structural and Electrical Properties of EOT HfO2 (<1 nm) Grown on InAs by Atomic Layer Deposition and Its Thermal Stability.
abstract: We report on changes in the structural, interfacial, and electrical characteristics of sub-1 nm equivalent oxide thickness (EOT) HfO2 grown on InAs by atomic layer deposition. When the HfO2 film was deposited on an InAs substrate at a temperature of 300 °C, the HfO2 was in an amorphous phase with an sharp interface, an EOT of 0.9 nm, and low preexisting interfacial defect states. During post deposition annealing (PDA) at 600 °C, the HfO2 was transformed from an amorphous to a single crystalline orthorhombic phase, which minimizes the interfacial lattice mismatch below 0.8%. Accordingly, the HfO2 dielectric after the PDA had a dielectric constant of ∼24 because of the permittivity of the well-ordered orthorhombic HfO2 structure. Moreover, border traps were reduced by half than the as-grown sample due to a reduction in bulk defects in HfO2 dielectric during the PDA. However, in terms of other electrical properties, the characteristics of the PDA-treated sample were degraded compared to the as-grown sample, with EOT values of 1.0 nm and larger interfacial defect states (Dit) above 1 × 10(14) cm(-2) eV(-1). X-ray photoelectron spectroscopy data indicated that the diffusion of In atoms from the InAs substrate into the HfO2 dielectric during the PDA at 600 °C resulted in the development of substantial midgap states.
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University , Seoul 120-749, Korea.
authors.forename: Yu-Seon
authors.initials: YS
authors.lastname: Kang
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University , Seoul 120-749, Korea.
authors.forename: Hang-Kyu
authors.initials: HK
authors.lastname: Kang
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University , Seoul 120-749, Korea.
authors.forename: Dae-Kyoung
authors.initials: DK
authors.lastname: Kim
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University , Seoul 120-749, Korea.
authors.forename: Kwang-Sik
authors.initials: KS
authors.lastname: Jeong
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University , Seoul 120-749, Korea.
authors.forename: Min
authors.initials: M
authors.lastname: Baik
authors.affiliation: School Department of Material Science and Engineering, Sungkyunkwan University , Suwon 440-746, Korea.
authors.forename: Youngseo
authors.initials: Y
authors.lastname: An
authors.affiliation: School Department of Material Science and Engineering, Sungkyunkwan University , Suwon 440-746, Korea.
authors.forename: Hyoungsub
authors.initials: H
authors.lastname: Kim
authors.affiliation: Center of Optoelectronic Materials, Korea Institute of Science and Technology , Seoul 136-791, Korea.
authors.forename: Jin-Dong
authors.initials: JD
authors.lastname: Song
authors.affiliation: Institute of Physics and Applied Physics, Yonsei University , Seoul 120-749, Korea.
authors.forename: Mann-Ho
authors.initials: MH
authors.lastname: Cho
keywords: HfO2; InAs; band alignment; indium arsenide; interfacial defect states; interfacial reactions