Low temperature deposition of TiN in an ECR plasma enhanced process

High quality TiN layers were deposited in an electron cyclotron resonance (ECR) plasma process at substrate temperatures between 100 and 600 degree C. Tetrakis(dimethylamido)-titanium Ti(NMe2)4 was used as the precursor and introduced into the downstream region of an ECR plasma. Nitrogen or ammonia have been used as the plasma gases. The electrical properties and the film compositions of the gold-colored TiN layers mainly depend on the deposition rate. ECR plasma activated nitrogen or ammonia react with Ti(NMe2)4 to form low resistivity (100-150 MyOmegacm) crystalline TiN films at substrate temperatures as low as 100 degree C. Films deposited between 200 and 600 degree C exhibit resistivities that decrease from 100 to 45 MyOmegacm. Crystalline orientation is influenced by the plasma gas. Preferred growth in the (111) and (100) directions is found when using ammonia and nitrogen, respectively. Experiments with labeled nitrogen show that the nitrogen for the TiN formation is almost exclu sively derived from the plasma gas. Chemical ionization mass spectrometry (CIMS) investigations of the gas mixture in the reactor using nitrogen as the plasma gas reveals the formation of amines, ammonia, hydrocyanic acid, and hydrogen. The deposits were characterized by four point probe resistivity measurements, X-ray diffraction (XRD), forward recoil scattering (FRS), Rutherford backscattering spectrometry (RBS), and electron probe micro analysis (EPMA). The microstructure and morphology were investigated by transmission electron microscopy (TEM) and atomic force microscopy (AFM), respectively.