Trimethylamine Complexes of Alane as Precursors for the Low-Pressure Chemical Vapor Deposition of Aluminum

Aluminum films were deposited in a hot-wall, low-pressure chemical vapor deposition reactor at temperatures as low as 100 degrees C by using (Me3N)(2)AlH3. Typical growth conditions were 180 degrees C substrate temperature and 25 degrees C for the precursor temperature. No carrier gas was used in any of the depositions, and the deposition rate on Si(100) under the above conditions was 0.9 mu m/min. Changing the substrate temperature to 280 degrees C resulted in an increase in the deposition rate to 3 mu m/min. Substrate materials included glass, polyimide films, and Si wafers. The surface morphology of the films was rough under most conditions. Pretreating the surface with TiCl4 allowed smoother films to be deposited at lower temperatures. At 100 degrees C mirrorlike films were grown that exhibited a high degree of crystallite orientation. The (111) layers were found parallel to the surface. Resistivities of the as-deposited films ranged from 2.8 to 4.5 mu Omega cm. A discussion of the deposition chemistry and a comparison to depositions using triisobutylaluminum are presented.