STTR Phase II: A Fiber-Optic Probe for In-Situ Measurement of Thin Film Deposition

*** 9805281约翰逊 几乎所有现代光电器件的性能都取决于生长多层薄膜结构的能力，这些结构的成分和厚度都得到精确控制。在生产规模的沉积工艺中，这些现在不能被真实的实时地监测和调节。我们将克服的问题，双光源，光纤，厚度和成分监测器同时作为干涉仪（测量生长速率）和反射计（测量成分和总厚度）。这种仪器的一个主要优点是它能够提供在生长过程中进行瞬时成分变化所需的数据，以补偿扩散的影响。当必须在相对高的温度下沉积非常薄的不同组成的相邻层时，扩散是一个重要因素，如多量子阱器件的情况。 第一阶段将把联合收割机激光和白色光源结合在一个诊断仪器中，该仪器与高温工艺兼容，不受电磁噪声（射频晶片加热的副产品）的影响，并且不需要精确的光学对准。光纤监测器的基本概念已经在布朗大学氮化硅反应堆的基本脉冲激光实验中得到了证明;主要研究人员已经成功地从白光反射光谱中提取了实时层成分。第一阶段将扩展这一早期的工作，以一个实际的双源配置快速和准确地跟踪薄膜生长的速度典型的先进设备。 反馈控制是关键，因为新的光电器件对生长过程提出了更高的要求;价格合理、易于使用的厚度和成分监测器的年市场将达到数百万美元。一 能力较低的版本将与石英沉积计竞争，每年有数千万的市场。 ***

*** 9805281 Johnson The performance of virtually all modem opto-electronic devices depends critically upon the ability to grow multi-layered, thin-film structures whose composition and thickness is precisely controlled. In production-scale deposition processes, these cannot now be monitored and adjusted in real time. We will overcome the problem with a dual-light-source, fiber-optic, thickness and composition monitor operating simultaneously as an interferometer (measuring growth rate) and as a reflectometer (measuring composition and total thickness). A major advantage of such an instrument is its ability to provide the data needed to make instantaneous composition changes during growth to compensate for the effects of diffusion. Diffusion is an important factor when very thin adjacent layers of dissimilar composition must be deposited at relatively high temperature, as is the case for multiple quantum well devices. Phase I will combine laser and white light sources in a single diagnostic instrument compatible with high-temperature processes, immune to electromagnetic noise (a byproduct of rf wafer heating), and free of the requirement for precise optical alignment. The basic concept of the fiber-optic monitor has been demonstrated in rudimentary pulsed laser experiments on a silicon nitride reactor at Brown University; the principal investigator has successfully extracted real-time layer composition from white-light reflectance spectra. Phase I will extend this earlier work to a practical dual-source configuration fast and accurate enough to track thin-film growth at rates typical of advanced devices. Feedback control is key as new optoelecelectonic devices place greater demands on growth processes; the annual market for reasonably priced, easy to use thickness and composition monitors will be several million dollars. A less capable version would compete with quartz deposition gauges, with a market of tens of millions per year. ***