Nd2O3掺杂的HfO2高k栅介质薄膜ALD制备及性能研究

Characteristics of Nd2O3-Doped HfO-2 High-k Gate Dielectric Films Prepared by Atomic Layer Deposition

采用原子层沉积技术（ALD）制备了Nd2O3掺杂的HfO2高k栅介质薄膜（Hf-bid-O），通过x射线光电子能谱（XPS）研究了薄膜中元素的成分、结合能及化学计量比，分析了Nd2O3掺杂后薄膜中氧空位浓度和界面层成分的变化；通过测量薄膜的光致发光（PL）图谱，比较了Nd2O3掺杂前后铪基薄膜中的氧空位浓度变化，分析了Nd2O3掺杂对HfO2薄膜中氧空位浓度的影响；通过高分辨率透射电子显微镜（HR-TEM）研究了薄膜厚度及形态；制备了Pt／HfO2（Hf-Nd-O）／lL／n-Si／AgMOS结构，应用半导体参数测试仪得到薄膜的电容-电压（C-V）和漏电流密度-电压（J-V）特性曲线。结果表明，Nd2O3掺入HfO2薄膜后，整个铪基薄膜体系的氧空位减少，Hf-O键的结合能提高，Hf和O的原子比更接近理想的化学计量比（1：2）；在同样物理厚度与界面制备工艺条件下，Nd2O3的掺入使得MOS结构的饱和电容值提高，EOT降低，Vg=（Vfb＋1）V时，Nd2O3掺杂的HfO2薄膜的漏电流密度为8．7×10-3A·cm2，相比于纯HfO2薄膜的3．5×10-2A·cm2有明显降低，电学性能整体得到提高。

The Nd2O3-doped HfO2 films were prepared by atomic layer deposition （ALD）. The binding energy of elementswas char- acterized by X-ray photoelectron spectroscopy （XPS）. The photoluminesccnce （PL） was used to compare the oxygen vacancy in the films. The reasons for the change of the oxygen vacancy concentration in the films after Nd2O3 doping were analyzed. The thickness and morphology of the films were investigated by high resolution transmission electron microscopy （HRTEM）. MOS structures were made to characterize the leakage current and capacitance. The results showed that the oxygen vacancy decreased, the binding energy of Hf-O bond increased and the atomic ratio of Hf to O was closer to the stoiehiometric ratio （ 1 ： 2 ） after Nd2O3 doping. Under the same physical thickness and interfacial preparation conditions, the doping of Nd2O3 increased the saturation capacitance of the MOS structure, and reduced the EOT. The leakage current density of Nd2O3 -doped HfO2 thin films was 8.7×10-3A·cm2 at Vg = （ Vfb ＋ 1 ） V, significantly lower than that of pure HfO2 thin films （3.5×10-2 A .cm2） , showing the improvement in the overall electrical performance.