Maslar James E, Kimes William A, Sperling Brent A, Kanjolia Ravindra K
Material Measurement Laboratory, National Institute of Standards and Technology 100 Bureau Drive, Gaithersburg, MD 20899, USA.
EMD Performance Materials, Haverhill, MA 01832, USA.
J Vac Sci Technol A. 2019;37(4). doi: 10.1116/1.5099264.
The performance of a bubbler to deliver the low-volatility, liquid cobalt precurso - -(Bu-acetylene) dicobalthexacarbonyl (CCTBA) for reduced-pressure chemical vapor deposition and atomic layer deposition processes was characterized. A relatively large process window was investigated by varying carrier gas flow rate, system pressure, and bubbler temperature. For this range of conditions, the CCTBA partial pressure was measured using a custom-designed non-dispersive infrared gas analyzer, and the CCTBA flow rates were derived from these partial pressure measurements. The dependence of CCTBA flow rate on these process parameters was modeled to obtain a deeper understanding of the factors influencing bubbler performance. Good agreement between measured and modeled CCTBA flow rates was obtained using a model in which a constant CCTBA partial pressure in the bubbler head space for a given bubbler temperature was assumed and in which the pressure drop between the bubbler head space and the pressure measurement location was included. The dependence of CCTBA head space partial pressure on temperature was parameterized in the form of the August equation, which is commonly used to describe the temperature-dependence of vapor pressure. While this report was focused specifically on CCTBA, the results are expected to apply to other low-volatility, liquid precursors of interest in vapor deposition processes.
对一种用于减压化学气相沉积和原子层沉积工艺的鼓泡器输送低挥发性液体钴前驱体——（丁酮-乙炔）二钴六羰基（CCTBA）的性能进行了表征。通过改变载气流量、系统压力和鼓泡器温度，研究了一个相对较大的工艺窗口。在此条件范围内，使用定制设计的非色散红外气体分析仪测量CCTBA分压，并根据这些分压测量值推导出CCTBA流量。对CCTBA流量与这些工艺参数的相关性进行建模，以更深入地了解影响鼓泡器性能的因素。使用一个模型获得了测量的和建模的CCTBA流量之间的良好一致性，该模型假设在给定鼓泡器温度下鼓泡器顶部空间的CCTBA分压恒定，并考虑了鼓泡器顶部空间与压力测量位置之间的压降。CCTBA顶部空间分压对温度的依赖性以奥古斯特方程的形式进行参数化，该方程通常用于描述蒸气压的温度依赖性。虽然本报告专门针对CCTBA，但预计这些结果适用于气相沉积工艺中其他感兴趣的低挥发性液体前驱体。
