Control of Intrinsic Stresses in Ceramic Thin Films and Coatings Produced by Chemical Vapor Deposition

化学气相沉积陶瓷薄膜和涂层内应力的控制

• 批准号: 0075207
• 负责人: Brian Sheldon
• 金额: $ 42.19万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-06-01 至 2004-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0075207&HistoricalAwards=false
• 关键词: Control; Intrinsic; Stresses; Ceramic; Thin

The primary motivation for this research project is the need to control residual stresses in ceramic thin films and coatings, which encompasses a wide range of materials used for both electronic and structural applications. Residual stresses arise from the thermal expansion mismatch between film and substrate, and from various intrinsic mechanisms during film growth. The viability of ceramic films and coatings are typically evaluated by calculating thermal stresses, however, this calculation is often inaccurate because it ignores intrinsic stresses. Previous work at Brown demonstrates that tensile stresses caused by island coalescence during film growth often overshadow thermal stresses. This work also shows that these intrinsic stresses can be controlled by altering processing during island coalescence. These efforts are focused on CVD diamond, which is an excellent system for these studies since diamond has large intrinsic stresses that are problematic for a number of applications and because the extensive literature on CVD diamond provides a strong basis for understanding growth stresses. Building on the previous success with CVD diamond, the following activities will be carried out during the project: 1) Establish that intrinsic tensile stresses can be controlled by altering processing during grain coalescence in a wide range of ceramic thin films and coatings; 2) Develop better models for describing the evolution of intrinsic stresses; 3) Investigate relationships between residual stress and film properties (fracture, etc.), which will be based on the processing methods developed at Brown that provide a unique approach for varying stress without changing the substrate, grain size, or film composition; 4) Control intrinsic stresses to modify the total residual stress in novel ways; 5) Investigate discrepancies between Raman spectroscopy and other methods that are used to measure residual stress in CVD diamond; 6) Provide direct input to ongoing work on oxide coatings at Oak Ridge National Laboratory; and 8) Continue a variety of educational efforts, including the ExSEL program at Brown (co-PI Prof. Rankin), and an accredited Materials Science workshop for local middle and high school teachers that was developed by the PI. Research activities will continue to involve undergraduates from both Brown and Trinity (an undergraduate teaching institution). %%%Ceramic and diamond thin films are used in a variety of technologically important applications such as computers and telecommunications. During processing these thin films are develop stress that limit their effectiveness in the application. This research project, which will be carried out by two investigators at Brown University and one from Trinity College (an undergraduate institution), will investigated methods of controlling the stress that form. The results from this work will lead to better understanding and improved control of stresses in a variety of thin films and coatings, thus enhancing their usage in the application.***

该研究项目的主要动机是需要控制陶瓷薄膜和涂层中的残余应力，其中包括用于电子和结构应用的各种材料。 残余应力的产生是由于薄膜和衬底之间的热膨胀失配以及薄膜生长过程中的各种内在机制。 陶瓷薄膜和涂层的生存能力通常通过计算热应力来评估，然而，这种计算通常是不准确的，因为它忽略了内应力。布朗大学以前的工作表明，在薄膜生长过程中由岛聚结引起的拉伸应力往往掩盖了热应力。这项工作还表明，这些内应力可以通过改变岛屿合并期间的加工过程来控制。这些努力都集中在CVD金刚石，这是一个很好的系统，这些研究，因为金刚石具有很大的内在应力，这是有问题的一些应用，因为大量的文献CVD金刚石提供了一个强大的基础，了解生长应力。 在CVD金刚石成功的基础上，项目期间将开展以下活动：1）确定在各种陶瓷薄膜和涂层中，通过改变晶粒聚结过程中的工艺可以控制内在拉伸应力; 2）开发更好的模型来描述内在应力的演变; 3）研究残余应力与膜特性（断裂等）的关系，这将是基于在布朗开发的处理方法，提供了一个独特的方法来改变应力，而不改变衬底，晶粒尺寸，或薄膜成分; 4）控制内在应力，以修改总的残余应力，以新的方式; 5）调查之间的差异拉曼光谱和其他方法，用于测量CVD金刚石残余应力; 6）为橡树岭国家实验室正在进行的氧化物涂层工作提供直接投入; 8）继续开展各种教育工作，包括布朗的ExSEL计划（联合PI教授兰金），以及PI为当地初中和高中教师开发的经认可的材料科学研讨会。 研究活动将继续涉及布朗大学和Trinity（一所本科教学机构）的本科生。%陶瓷和金刚石薄膜用于各种重要的技术应用，如计算机和电信。 在加工过程中，这些薄膜受到显影应力，这限制了它们在应用中的有效性。 这项研究项目将由布朗大学的两名研究人员和Trinity学院（一所本科院校）的一名研究人员进行，研究控制压力形成的方法。这项工作的结果将导致更好地理解和改善各种薄膜和涂层中的应力控制，从而提高它们在应用中的使用。