Modeling and Validation of Sensor and Actuator Dynamics for, And Real-Time Feedback Control of Thermal Chlorine Etching of Gallium Arsenide

A dynamic model for the simulation of thermal chlorine etching of gallium arsenide is developed. The primary motivation for the development of the model is the design and testing of real time feedback controllers which rely upon in-situ optical measurements of etch depth obtained via spectroscopic ellipsometry. Unmeasurable parameters which appear in the model are identified, and the model is validated using experimental data. A linear-quadratic controller based on our model is designed and tested.