LOW-TEMPERATURE DEPOSITION OF TIN USING TETRAKIS(DIMETHYLAMIDO)-TITANIUM IN AN ELECTRON-CYCLOTRON-RESONANCE PLASMA PROCESS

High quality TiN layers were deposited in an electron cyclotron resona nce (ECR) plasma process at substrate temperatures between 100 and 60- degrees-C. Tetrakis(dimethylamido)-titanium [Ti(NMe2)4] was used as th e precursor and introduced into the downstream region of an ECR plasma . Nitrogen or ammonia have been used as plasma gases. The electrical p roperties and the film compositions of the gold-colored TiN layers mai nly depend on the deposition rate. ECR plasma-activated nitrogen or am monia reacts with Ti(NMe2)4 to form low resistivity (100-150 muOMEGAcm ) crystalline TiN films even at a substrate temperature of 100-degrees -C. Films deposited between 200 and 600-degrees-C exhibited resistivit ies that decreased from 100 to 45 muOMEGAcm. Crystalline orientation i s influenced by the chosen plasma gas. Preferred growth in the (111) a nd (100) directions were found by using ammonia and nitrogen, respecti vely The measured resistivities and deposition temperatures are the lo west reported values for a plasma-enhanced TiN deposition process. Exp eriments with labeled nitrogen show that the nitrogen for the TiN form ation is almost exclusively derived from the plasma gas. The deposits were characterized by four-point probe resisivity measurements, x-ray diffraction, forward recoil scattering, and Rutherford backscattering spectrometry. Step-coverage was checked by a scanning electron microsc opy cross section of a contact via.