As novel semiconductor and dielectric materials become more prevalent in MOS device technology, MOS capacitors are used to investigate the quality of semiconductor/dielectric, semiconductor/contact, and dielectric/metal gate interfaces, through capacitance-voltage (C-V) and I-V testing along with physical materials characterization. Thermal processes such as implant stabilization, contact annealing, and dielectric postdeposition annealing must be managed to accomplish the desired results while minimizing undesirable side effects such as interdiffusion or dopant migration in devices. This can be done through a combination of device and process design, which prevents these unwanted effects through careful material selection, ordering of process steps, temperature adjustments where possible, and selection of process gases used during thermal treatments. This study focuses on the effects of a 430 °C forming gas anneal, which produced an unusual brown layer on Ti/Au metal-oxide-semiconductor capacitor gates. A series of experiments, XPS analysis, and C-V electrical data revealed that the brown layer was not an organic residue but a thin layer of TiO₂ on the gold surface, which formed due to Ti diffusion to the Au surface during the forming gas anneal. Oxygen plasma treatment before the furnace anneal enhanced the undesirable diffusion effect. Replacing the Ti/Au gates with Cr/Au gates prevented the brown layer and improved capacitance-voltage characteristics.

中文翻译：

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Si/Al2O3/Ti/Au 金属氧化物半导体电容器中的钛扩散

随着新型半导体和介电材料在 MOS 器件技术中变得越来越普遍，MOS 电容器被用于研究半导体/电介质、半导体/触点和电介质/金属栅极界面的质量，通过电容电压 (CV) 和 IV 测试以及物理材料表征。必须管理诸如注入稳定、接触退火和电介质沉积后退火之类的热工艺，以实现所需的结果，同时最大限度地减少不希望的副作用，例如器件中的相互扩散或掺杂剂迁移。这可以通过设备和工艺设计的组合来实现，通过仔细的材料选择、工艺步骤的排序、可能的温度调整来防止这些不良影响，以及热处理过程中使用的工艺气体的选择。本研究侧重于 430 °C 合成气体退火的影响，该退火在 Ti/Au 金属氧化物半导体电容器栅极上产生了不寻常的棕色层。一系列实验、XPS 分析和 CV 电学数据表明，棕色层不是有机残留物，而是一层薄薄的 TiO₂在金表面上，这是由于在合成气体退火过程中 Ti 扩散到 Au 表面而形成的。炉退火前的氧等离子体处理增强了不希望的扩散效应。用 Cr/Au 栅极代替 Ti/Au 栅极可防止褐色层并改善电容-电压特性。