LOW-TEMPERATURE METAL-ORGANIC CHEMICAL-VAPOR-DEPOSITION OF ADVANCED BARRIER LAYERS FOR THE MICROELECTRONICS INDUSTRY

Metal-organic chemical vapor deposition (MOCVD) of TiN thin films at l ow temperatures and low pressures using tetrakis(diethylamino)Ti (TDEA T) and NH3 is described. Conformal TN films, having layer resistivitie s of less than 200 muOMEGA cm, densities close to those in sputtered f ilms and low impurity contents can be obtained with this chemistry. Th ese TiN films can be applied as adhesion layers for chemically vapor-d eposited W, or as barrier layers between Si and Al. Many papers descri be deposition of TiN using tetrakis(dimethylamino)Ti (TDMAT) and NH3 t o form TiN, presumably because of the conveniently higher vapor pressu re of TDMAT compared with TDEAT. A direct liquid injection system is u sed here to enable reproducible introduction of both amines in the rea ctor. A direct comparison between the TDMAT-NH3 and TDEAT-NH3 chemistr ies and the properties of the resulting films is made. It is found tha t the more reactive TDMAT-NH3 chemistry produces non-conformal films h aving a higher resistivity (> 1200 muOMEGA cm) and lower density. Fina lly, MOCVD of advanced amorphous barrier materials, comprising a terna ry Ti-Si-N alloy, is described. Such amorphous ternary barriers are ca ndidates for application in future Cu metallization schemes.