Fundamental Studies of Thermal Plasma Chemical Vapor Deposition

这是热等离子体化学气相沉积的基础研究。(TPCVD)，目标是将TPCVD发展为高速沉积高质量硬膜和涂层的可靠工艺。用1托~1大气压的感应耦合射频等离子体沉积碳化硼和碳化硅薄膜。反应物是适当的氯化物蒸气(三氯化硼或四氯化硅)和甲烷，注入氢-氩等离子体中。薄膜通过多种非原位技术进行表征，以确定元素组成、结晶度、形貌、化学结合、硬度和相关的机械性能。薄膜的生长速度和性能与操作条件、表面温度和生长表面附近的流体边界层的化学成分有关。分子束质谱(MBMS)用于在线测量沉积过程中气相物质的摩尔分数；这项技术可以提供超过光谱仪检测下限(Ppm)的所有物种的摩尔分数的绝对测量。建立了生长表面化学反应边界层的数值模型，并使用MBMS测量进行了测试。本课题可能是生产耐磨和耐化学侵蚀涂层的主要使能技术。两名研究生正在接受涉及传热学、等离子体科学、化学和材料科学的高级实验和计算方法的跨学科培训。此外，还开发了一种用于等离子体沉积研究的新的诊断方法(MBMS)。

Abstract-GirshickThis is a fundamental study of thermal plasma chemical vapor deposition. (TPCVD) with the objective of developing TPCVD as a robust process for the high-rate deposition of high-quality hard films and coatings. An inductively coupled radio-frequency plasma at pressures of 1 Torr to 1 atmosphere is used to deposit films of boron carbide and silicon carbide. Reactants are the appropriate chloride vapor (boron trichloride or silicon tetrachloride) and methane, injected into an argon-hydrogen plasma. Films are characterized by several ex-situ techniques to determine elemental composition, crystallinity, morphology, chemical bonding, hardness and related mechanical properties. Film growth rates and properties are related to operating conditions, surface temperature, and the chemistry of the fluid boundary layer adjacent to the growth surface. Molecular-beam mass spectrometry (MBMS) is used to obtain on-line measurements of mole fractions of gas-phase species during deposition; this technique can provide absolute measurements of mole fraction for all species present above the detection limit (ppm) of the spectrometer. Numerical models of the chemically reacting boundary layer at the growth surface are developed and tested using MBMS measurementsThis topic is potentially a major enabling technology for production of coatings resistant to abrasion and chemical attack. Two graduate students are receiving interdisciplinary training in advanced experimental and computational methods involving heat transfer, plasma science, chemistry, and materials science. In addition, a new diagnostic (MBMS) for plasma deposition studies is developed.