Abstract

Ge-based metal-oxide semiconductor structures exhibiting thin ALD-grown high-k dielectric HfO₂ films were fabricated and characterized chemically, structurally, and electrically. X-ray photoelectron (XP) spectroscopy confirms the good stoichiometry of the ALD-grown HfO₂ films. Furthermore, through the analysis of the XP spectra, the conduction and valence band offsets of HfO₂|p-Ge were calculated to be equal to 1.8 ± 0.2 eV and 2.8 ± 0.2 eV, respectively. C(V) and G(V) analysis reveals structures with a well-defined MOS behavior with D_it values in the range of 10¹¹ eV^–1 cm^–2 and a dielectric constant of HfO₂ films of 20. The dominant carrier transport conduction mechanisms were studied through J(V) analysis, performed at both substrate and gate electron injection. Specifically, in the low voltage region (V < 0.2 V), the prevailing conduction mechanism is Ohmic, with an activation energy of 0.28 eV for both substrate and gate electron injection. In the voltage range 0.4–1.5 V, the dominant conduction mechanism is Frenkel–Poole, through which the trap energy level into HfO₂ films (φ_t) is calculated to be φ_t = 0.36 eV. Schottky conduction mechanism is the prevailing one, for high applied bias voltages (V > 3.0 V) and high temperatures (>450 K). Applying Schottky’s emission model the energy barrier heights of HfO₂|p-Ge and Al|HfO₂ interfaces were evaluated equal to 1.7 ± 0.2 eV and 1.3 ± 0.2 eV, respectively. Combining the XPS and J(V) analysis results, the energy band diagram of Al|HfO₂|p-Ge structures is constructed. The calculated values of conduction and valence band offsets via XPS and J(V) measurements are in very good agreement.

中文翻译：

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Al | HfO 2的界面表征和输运传导机理 p -Ge结构：能带图

摘要

制备了具有ALD生长的高k介电HfO ₂薄膜的Ge基金属氧化物半导体结构，并对其进行了化学，结构和电学表征。X射线光电子（XP）光谱证实了ALD生长的HfO ₂膜的良好化学计量。此外，通过XP光谱分析，HfO ₂ |的导带和价带偏移。计算出的p -Ge分别等于1.8±0.2 eV和2.8±0.2 eV。C（V）和G（V）分析揭示了具有明确MOS行为的结构，D _it的值在10范围内。¹¹ eV ^–1 cm ^–2的HfO ₂薄膜的介电常数为20。通过J（V）分析研究了主要的载流子传输传导机理，该分析是在衬底和栅电子注入时进行的。具体而言，在低压区域（V <0.2 V），主要的传导机制是欧姆，对于衬底和栅极电子注入，其激活能均为0.28 eV。在电压范围0.4-1.5 V，占主导地位的传导机制是弗伦凯尔-普尔，通过该陷阱能级到的HfO _2层膜（φ_吨）被计算为φ_吨= 0.36 eV。对于高施加的偏置电压（V > 3.0 V）和高温（> 450 K），肖特基传导机制是主要的机制。应用肖特基二极管发射模型重燃油的能量势垒高度₂ | 对p -Ge和Al | HfO ₂界面的评估分别等于1.7±0.2 eV和1.3±0.2 eV。结合XPS和J（V）分析结果，得​​出Al | HfO ₂ |的能带图。构造了p -Ge结构。通过XPS和J（V）测量得出的导带和价带偏移的计算值非常吻合。