Metalorganic chemical vapor deposition of aluminum from trimethylamine alane using Cu and TiN nucleation activators

Abstract

High purity Al films have been deposited on TiN and in situ evaporated Cu films on Si in a cold wall low pressure metalorganic chemical vapor deposition reactor using trimethylamine alane. TiN and Cu serve as nucleation layers for Al deposition to replace the commonly used but corrosive TiCl4. Al films deposited on TiN at 250 °C exhibit highly textured (111) orientation, whereas those grown on Cu at 150–350 °C are randomly oriented with some preferential growth in the (100) direction. These films are compared with films grown on Si and SiO2 using TiCl4 activation. Cu serves the additional purpose of diffusing into the Al during deposition to improve the electromigration resistance of the films. Electrical resistivities of the Al films on TiN are 4–6 μΩ cm, roughly twice that of bulk Al. The variation of film morphology with deposition temperature, substrate, and precursor pressure is discussed.