Remote Plasma-Assisted Metal Organic Chemical Vapor Deposition of Tantalum Nitride Thin Films with Different Radicals

Abstract

Thin films of tantalum nitride have been deposited from remote plasma-assisted metal organic chemical vapor deposition (RP-MOCVD) using the reaction of pentakis-dimethyl-amino-tantalum (PDMATa) with different activated radicals. Microstructures of deposited films measured by X-ray diffraction (XRD) and transmission electron microscopy (TEM) depend on the deposition temperature and the type of radicals. At temperatures below 300°C, amorphous films are obtained which are independent of the reacting species. On the other hand, at higher deposition temperatures, (111)-preferred cubic TaN films are obtained when they react with ammonia plasma, while the reaction with hydrogen plasma produces amorphous films. All amorphous films obtained are recrystallized at an annealing temperature of 1000°C in an oxygen-containing (10%) ambient, showing (111) TaN, bcc Ta, and signals of orthorhombic Ta2O5. From detailed studies of film composition and chemical bonding in the obtained films, the impurity incorporation, especially carbon, is responsible for the dependence of film microstructures on different deposition conditions.