Chemical Sensors for CVD Processing

本文旨在理解和设计一种基于化合物半导体表面吸附的新型光致发光化学传感器。以前的工作已经确定了这种方法的可行性。由于传感器基底的可逆化学吸附而在半导体近表面区域发生的变化；半导体表面区域耗尽宽度的调制导致从这些结构中观察到的光致发光强度的变化。该项目的重点是研究具有高灵敏度和高探测性的传感材料和材料结构。使用现代外延技术，如金属有机气相外延（MOVPE），可以生产定制的工程材料结构，以增强半导体对特定吸附物质的响应。新的化学方法来传感各种技术上重要的底物，包括硅烷和组III和组V CVD前体，探索。开发了利用电子传递和光致发光作为传感信号的新型传感装置，并对其进行了建模。还探讨了传感器结构长期退化的原因和抑制这种变化的方法。迫切需要新的传感器设计和实现方法；在某些情况下，例如半导体加工，传感器可能是提高质量和推进设计实施的限制因素。这项工作将半导体器件技术应用于生产小型、廉价、坚固的传感器，而不需要机械部件。所研究的特定系统适用于化合物半导体和固态器件的生产。基本方法具有更广泛的适用性。＊＊＊

ABSTRACT CTS-9510099 This effort is directed to the understanding and design of novel photoluminescent chemical sensors based upon adsorption onto a compound semiconductor surface. Previous work has established the feasibility of this approach. Changes in the near-surface region of the semiconductor due to reversible chemisorption form the basis of the sensor; modulation of the depletion width of the surface region of the semiconductor leads to changes in the photoluminescence intensity observed from these structures. The thrust of this project is concerned with sensing materials and materials structures with high sensitivity and high detectivity. The use of modern epitaxial techniques such as metalorganic vapor-phase epitaxy (MOVPE) allows production of engineered materials structures tailored to enhance the response of the semiconductor to the specific adsorbed species. New chemical approaches to sensing a wide variety of technologically important substrates, including silanes and group III and group V CVD precursors, are explored. New sensing devices in which electron transport as well as photoluminescence is used as the sensor signal are developed and modeled. Causes of long-term degradation of the sensor structures and means to inhibit such changes are also explored. New approaches to sensor design and implementation are badly needed; in some cases, such as semiconductor processing, sensors may be the limiting factor in improving quality and advancing design implementation. This effort applies semiconductor device technology to the production of small, inexpensive, robust sensors without mechanical components. The specific systems under study are applicable to the production of compound semiconductors and solid-state devices. The basic approach has a much broader applicability. ***