This award is made in the Special Projects Office of the Chemistry Division under the Materials Synthesis and Processing Initiative. The research will address the problem of formation of thin films of compound materials by chemical vapor deposition (CVD) from organometallic precursors. The intent is to correlate the basic gas phase and surface chemical behavior of the precursors with the structure and purity of the resulting films, and with the efficiency of precursor conversion to final product. The system to be investigated is the production of AlN films from organoaluminum-ammonia or -amide precursors containing aluminum and nitrogen in the correct stoichiometric ratio. The gas phase and surface chemistry of these precursors will be studied using a combination of mass spectrometry with time-of-flight measurements of product species, and pulsed beam Fourier transform microwave spectroscopy. Thin film deposition will be carried out in a cold-wall, hot-stage CVD system. Films formed in this system and in the course of the surface chemistry studies will be characterized by a range of surface and analytical techniques to determine their composition, structure and orientational relationships. %%% This study will provide a comprehensive picture of the steps leading from precursor to film in AlN deposition, and in the process identify the critical reaction steps controlling composition and structure. This information can also be used in the design of improved precursor systems for AlN as well as serving as a paradigm for the CVD of other electronic and ceramic systems.
