超臨界流体堆積法を用いたコンフォーマル酸化チタンのメモリや光触媒応用

本文提出了一种新的沉积工艺--超临界流体沉积法（SCFD），利用有机化合物（前驱体）在类液-气超临界CO2（scCO 2）中的热分解，以高的生长速率在高深宽比（AR）特征上实现TiO 2的共形沉积，并将其应用于三维存储器件。SCFD已用于在100纵横比（AR）特征上以~ 4 nm/min的相对高的沉积速率进行极保形的TiO 2沉积，而常规CVD-TiO 2在3D结构上具有差的保形性，并且保形ALD-TiO 2具有<0.5nm/min的低生长速率。在该项目中，考虑到TiO 2被认为是存储器中电容器的填料以及光催化剂，（正相）用于水分解，将自主开发的共形SCFD-TiO 2工艺应用于DRAM中的3D电容器。成功制备了RuO 2/TiO 2/RuO 2结构的二维和三维电容器。在平面衬底上对SCFD-TiO_2进行了I-V和C-V测试，其漏电流密度为10 ~（-6）A/cm ~ 2，击穿电压为0.6 MV/cm，介电常数约为70。这些值与通过常规CVD方法制备的那些样品相当。在JSPS的支持下，我们自主研发的TiO 2-SCFD在3D存储器件上进行了可行性验证，并初步探索了其作为水分解光催化剂的应用。

I proposed to employ a novel deposition process, supercritical fluid deposition (SCFD) of conformal TiO2, for applications on 3D memory device due to its conformal coverage on high aspect ratio (AR) features.SCFD involves the thermal decomposition of organic compounds (precursors) in the liquid-gas-like supercritical CO2 (scCO2), and is able to achieve conformal deposition with high growth rate on high aspect ratio features. SCFD has been employed for extremely conformal TiO2 deposition on 100 aspect ratio (AR) features with relatively high deposition rate of ~4nm/min, while conventional CVD-TiO2 has poor conformality on 3D structure and conformal ALD-TiO2 has low growth rate of < 0.5 nm/min.In this project, considering that TiO2 is regarded as dielectrics for capacitor in memory as well as a photocatalyst (anatase phase) for water splitting, the self-developed conformal SCFD-TiO2 process was applied for 3D-capacitor in DRAM. Both 2D and 3D capacitors with RuO2/TiO2/RuO2 configuration were fabricated successfully. I-V and C-V measurement were conducted for SCFD-TiO2 on planar substrate, which had the leakage density of 10-6 A/cm2, breakdown voltage of 0.6 MV/cm, and dielectric constant of ~70 were achieved. These values are comparable to those samples prepared by conventional CVD methods. With the support of JSPS, our self-developed TiO2-SCFD has demonstrated its feasibility on 3D memory devices, and its application as water splitting photocatalyst is explored preliminary as well.