AVS 45th International Symposium
    Vacuum Metallurgy Division Tuesday Sessions
       Session VM+TF-TuM

Paper VM+TF-TuM9
Investigation on Multilayered Chemical Vapor Deposited Ti/TiN Films

Tuesday, November 3, 1998, 11:00 am, Room 328

Session: Advances in Hard and Superhard Coatings
Presenter: J.C. Hu, National Tsing Hua Univ., Rep. of China
Authors: J.C. Hu, National Tsing Hua Univ., Rep. of China
T.C. Chang, National Nano Device Lab, Rep. of China
L.-J. Chen, National Tsing Hua Univ., Rep. of China
Y.L. Yang, National Nano Device Lab, Rep. of China
P.T. Liu, National Chiao Tung Univ., Rep. of China
S.Y. Chen, National Tsing Hua Univ., Rep. of China
C.Y. Chang, National Chiao Tung Univ., Rep. of China
Correspondent: Click to Email
As the device dimensions scale down to deep submicron level, chemical vapor deposition (CVD) for TiN films provided excellent step coverage and uniformity. Cu is likely to replace Al for interconnect metallization in future integrated circuits. On the other hand, the CVD-TiN films are usually of columnar structure. As a result, the fast diffusion of Al (or Cu) and Si atoms along TiN grain boundaries would degrade the device performance severely. In the present study, a novel multilayered CVD-Ti/TiN structure is formed to alleviate the grain boundary effects. To investigation the barrier property of the multilayered Ti/TiN films, junction leakage current was also measured. All the films were deposited by CVD processed in a MRC multichamber cluster tool, using TiCl@sub 4@, NH@sub 3@ and H@sub 2@ as reactants. The Ti and TiN films were deposited by plasma enhanced CVD and low pressure CVD, respectively. In order to reduce chlorine concentration of the films, NH@sub 3@ plasma post-treatment was applied to multilayered CVD-Ti/TiN films. In addition, electroless deposition of Cu was deposited on the multilayered CVD-Ti/TiN films. Transmission electron microscopy and X-ray diffractometry were utilized to investigate the microstructure and crystal orientation. Auger electron spectrocopy was applied to determine the stoichiometry and uniformity along the depth direction. The morphology was studied by a field emission scanning electron microscopy. Electrical measurement was used by HP-4145. The enhanced multilayered Ti/TiN stack found to be a robust barrier against Al/Si interdiffusion. It also improved the electrical property of the films. The resistivity of the film was found to reduce from 240 to 120 µm@OMEGA@-cm by multilayered Ti/TiN structure with the NH@sub 3@ plasma post-treatment. The leakage current can also be kept low enough for device application. In addition, the thermal stability of electroless Cu/mutilayered (CVD-Ti/TiN)/TiSi@sub 2@/Si structure was improved.