Structural and Electrical Properties of EOT HfO2 (<1 nm) Grown on InAs by Atomic Layer Deposition and Its Thermal Stability

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• 作者：Yu-Seon Kang ; Hang-Kyu Kang ; Dae-Kyoung Kim ; Kwang-Sik Jeong ; Min Baik ; Youngseo An ; Hyoungsub Kim ; Jin-Dong Song ; Mann-Ho Cho
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：March 23, 2016
• 年：2016
• 卷：8
• 期：11
• 页码：7489-7498
• 全文大小：824K
• ISSN：1944-8252

文摘

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 (D_it) above 1 × 10¹⁴ 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.