We report the comparison of the atomic layer deposited polycrystalline (p-)/amorphous (a-) HfO ₂ bilayer gate dielectric with p-HfO ₂ /a-Al ₂ O ₃ for enhanced $\beta $ -Ga ₂ O ₃ metal oxide semiconductor capacitors (MOSCAPs). A discrepancy in the temperature-dependent hysteretic behaviors is observed, and thus, pulse capacitance–voltage ( ${C}$ – ${V}$ ) measurements are employed to investigate interface properties at the border between the amorphous (Al ₂ O ₃ or HfO ₂ ) and polycrystalline (HfO ₂ ) oxide layers. The proposed p-HfO ₂ /a-HfO ₂ exhibits similar interface trap densities ( ${D}_{\text {it}}$ ) at the interface between the bilayer dielectric and $\beta \text {-Ga}_{{2}}\text {O}_{{3}}$ , and shows lower border trap density ( ${N}_{\text {bt}}$ ). An effective barrier height of 1.62 eV for the p-HfO ₂ /a-HfO ₂ with a breakdown field of 9.1 MV/cm, which is higher than 1.01 eV of p-HfO ₂ /a-Al ₂ O ₃ , is obtained from the current density-voltage ( ${J}$ – ${V}$ ) characteristics using the Folwer–Nordheim model. Moreover, as compared with a p-HfO ₂ single layer, the additional a-HfO ₂ layer on top of p-HfO ₂ is beneficial to improve hysteretic and leakage characteristics, while maintaining its high-quality interface. The p-HfO ₂ /a-HfO ₂ bilayer with improved interface properties as well as a large positive flat-band voltage of 4.7 V is a promising candidate for the metal/high- ${k}$ stack of $\beta $ -Ga ₂ O ₃ MOSCAPs.

中文翻译：

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多晶/非晶HfO ₂双层结构作为栅介质β-Ga ₂ O ₃ MOS电容器

我们报告比较原子层沉积的多晶（p-）/非晶（a-）HfO ₂双层栅极电介质与p-HfO ₂ / a-Al ₂ O ₃的增强作用 $ \ beta $ -Ga ₂ O ₃金属氧化物半导体电容器（MOSCAP）。观察到温度相关的磁滞行为存在差异，因此，脉冲电容-电压（ $ {C} $ – $ {V} $ ）测量用于研究非晶（Al ₂ O ₃或HfO ₂ ）和多晶（HfO ₂ ）氧化物层之间边界的界面性质 。提出的p-HfO ₂ / a-HfO ₂具有相似的界面陷阱密度（ $ {D} _ {\ text {it}} $ ）在双层电介质和 $ \ beta \ text {-Ga} _ {{2}} \ text {O} _ {{3}} $ ，并显示较低的边界陷阱密度（ $ {N} _ {\ text {bt}} $ ）。1.62电子伏特的有效势垒高度的p的HfO ₂ /α-的HfO ₂与9.1 MV / cm，这对的HfO高于1.01电子伏特的击穿场 ₂ /α-的Al ₂ ö ₃ ，从获得的电流密度-电压（ $ {J} $ – $ {V} $ ）的特性，使用Folwer-Nordheim模型。另外，作为与p相比较的HfO ₂单层中，附加一个-HFO ₂在p的HfO的顶层 ₂，有利于提高滞后和漏电特性，同时保持其高质量接口。具有改善的界面特性以及4.7 V的大正平带电压的p-HfO ₂ / a-HfO ₂双层是金属/高纯金属的有希望的候选者 $ {k} $ 一叠 $ \ beta $ -Ga ₂ O ₃ MOSCAP。