Low-Energy Path to Dense HfO2 Thin Films with Aqueous Precursor
Low-Energy Path to Dense HfO2 Thin Films with Aqueous Precursor
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DOI：
10.1021/cm102082j
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发表时间：
2011-02-22
影响因子：
8.6
通讯作者：
Keszler, Douglas A.
中科院分区：
文献类型：
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作者：
Jiang, Kai;Anderson, Jeremy T.;Keszler, Douglas A.
新的、稳定的水溶液被开发出来用于沉积高质量的HfO2薄膜。该溶液相对于化学计量盐的低离子强度提供了不需要有机添加剂直接自旋涂覆薄膜的方法。过氧化物介导溶液中的粒子相互作用，同时使前体物质形成膜的相对低能量途径得以实现。通过x射线衍射、FT-ER、电子探针微分析、扫描电镜和x射线反射率研究了薄膜的结构、化学和密度。这些测量结果共同表明，在中等温度下，前驱体很容易产生光滑和致密的HfO2薄膜。通过椭偏光谱和透射/反射测量研究了薄膜的光学特性。观测到的折射率（1.89-1.93）与通过气相沉积技术获得的折射率相当。通过将薄膜集成到电容器和薄膜晶体管中来评估介电性能。作为电容器介质的性能特点是泄漏电流密度< 10 nA/cm(2)（在1 MV/cm时）和击穿场高达5.5 MV/cm。作为具有非晶铟镓氧化锌通道的薄膜晶体管的栅极介质，薄膜具有较小的栅极泄漏，使晶体管的性能具有接近13 cm(2)/ v的增量迁移率。
New, stable aqueous solutions have been developed for the deposition of high-quality HfO2 thin films. The low ionic strength of the solution relative to a stoichiometric salt provides the means to directly spin coat a film without organic additives. Peroxide mediates particle interaction in the solution, while enabling relatively low-energy pathways for condensation of the precursor species to a film. Film structure, chemistry, and density are investigated by X-ray diffraction, FT-ER, electron-probe microanalysis, SEM, and X-ray reflectivity. Results from these measurements collectively reveal that smooth and dense HfO2 films are readily produced from the precursors with annealing at moderate temperatures. Optical properties of the films are studied by spectroscopic ellipsometry and transmission/reflection measurements. The observed refractive indices (1.89-1.93) are comparable to those achieved via vapor deposition techniques. Dielectric properties are evaluated through integration of the films into capacitors and thin film transistors. Performance as capacitor dielectrics is characterized by leakage current densities < 10 nA/cm(2) (at 1 MV/cm) and breakdown fields up to 5.5 MV/cm. As gate dielectrics in thin film transistors with amorphous indium gallium zinc oxide channels, the films exhibit small gate leakage, enabling transistor performance with incremental mobilities near 13 cm(2)/V.s.