In-situ Mass and Elasticity Monitoring of Emerging Materials at High Temperature

半导体行业已经成功地转向更小规模的设备，由于我们在纳米级表征新兴材料的能力不断提高。像扫描电子显微镜（SEM）、扫描隧道显微镜（STM）、透射电子显微镜（TEM）和原子力显微镜（AFM）这样的高度复杂、昂贵和标准的表征工具通常在非原位（在材料生长/沉积之后）使用并且在接近环境温度下操作。扩大新/新兴材料应用的关键障碍之一是在加工过程中进行原位表征并提供对材料性能的实时控制。对于在极高温度（高于900 K）下沉积/生长的材料，原位材料表征变得更具挑战性。一个这样的例子是在1200 K下对使用过渡金属上的化学气相沉积产生的单层石墨烯膜进行原位重量分析和机械测量。现有的方法不足以在高温下操作，并且通常依赖于在生长之后将石墨烯薄片手动转移到传感器或虚拟衬底的表面以用于进一步分析。手动转移过程容易发生表面污染和材料特性变化，从而影响样品的完整性。因此，迫切需要原位材料表征，以确保可靠性，适用于特定应用，并进而在新兴纳米材料的薄膜生长期间提供更好的控制挑战在于超越现有的昂贵方法，并提供一种稳健的、低成本的、易于集成的、以及类似于具有高温操作能力的基于石英的厚度监控的实时监控解决方案。在拟议的工作中，我们将探讨使用微机械双桨振荡器的几何形状作为原位质量和弹性监测传感器。这项工作还将探索物理（使用有限元方法）背后的解耦质量和弹性测量使用一个特殊的扭转谐振模式的振荡器。

The semiconductor industry has successfully moved towards smaller-scale devices due to continuous improvements in our ability to characterize emerging materials at the nanoscale. Highly sophisticated, expensive and standard characterization tools like scanning electron microscopy (SEM), scanning tunnelling microscopy (STM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) are typically used ex-situ (after material growth/deposition) and operate close to ambient temperature. One of the key barriers to up scaling the applications of new/emerging materials is to perform in-situ characterization and provide real-time control over material properties during processing. The in-situ material characterization becomes more challenging for materials deposited/grown at extremely high temperatures (above 900 K). One such example is performing in-situ gravimetric and mechanical measurements on monolayer graphene films produced using chemical vapour deposition on transition metals at 1200 K. The existing methods are not sufficient to operate under high temperatures and typically depend on manual transfer of graphene flakes after growth to the surface of sensor or dummy substrates for further analysis. The manual transfer process is prone to surface contamination and changes to material properties, thus compromising sample integrity. Therefore, there is an imminent need for in-situ material characterization to ensure reliability, suitability for a particular application and in turn provide better control during thin film growth of emerging nanomaterials (including 2D materials).The challenge is to look beyond the existing expensive methods and provide a robust, low-cost, easy-to-integrate, and real-time monitoring solution similar to a quartz based thickness monitoring with high temperature operation capabilities. In the proposed work, we will explore the use of a micro-machined double paddle oscillator geometry as in-situ mass and elasticity monitoring sensor. This work will also explore physics (using finite element methods) behind decoupling mass and elastic measurements using a special torsional resonance mode of the oscillator.