Modeling and optimization of a chemical vapor deposition reactor for the production of zirconium oxide film.

摘要

This thesis will examine a mathematical model based on the one-dimensional flow simplification for the production of zirconium oxide by CVD to determine how the variation of process parameters affects the deposition rates and the cost of production. Parameters that are varied in the study are: substrate temperature, reagent flow rate, vertical spacing between nozzle and substrate (z-spacing), and ratio of composition of reagents in flow. The model is an approximation of a bench-scale reactor built and operated at the Oak Ridge National Laboratory in Oak Ridge, Tennessee.; Chemical vapor deposition processing can be accomplished with a variety of reactors. To reduce production costs, it is desirable to carry out this reaction in an ambient pressure reactor using the least amount of reagents, time and energy. Two tools are used in this study: a mathematical model of the ORNL reactor titled, “Flow and Reaction Calculations for Stagnation Point Flow,” and written by Dr. Thomas L. Starr, University of Louisville, and COSTFXNCALC, a VBA macro used to manipulate the model systematically and give output of parameters and calculated values.; The use of these two tools show that from both a production rate and cost objective, the optimum parameters for production of zirconium oxide film are substrate temperature and z-spacing at the high end of the set ranges, and flow rate at the low in end of the set range or 1200°C, 1.5cm, and 500sccm, respectively.; These parameters give a deposition rate of 109.3 pm/hr and the percentage of ZrCl₄ used is 213%. Obviously, a usage of 213% is impossible. Based on the method the model uses to calculate the chloride usage, this number is not erroneous, but is misleading.