AVS 46th International Symposium
    Electronic Materials and Processing Division Wednesday Sessions
       Session EM-WeP

Paper EM-WeP3
Effects of Deposition Temperature of Co Thin Films on (100)Si

Wednesday, October 27, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: H.Y. Huang, National Tsing Hua University, Taiwan, R.O.C.
Authors: H.Y. Huang, National Tsing Hua University, Taiwan, R.O.C.
L.-J. Chen, National Tsing Hua University, Taiwan, R.O.C.
W.F. Wu, National Nano Device Laboratories, Taiwan, R.O.C.
R.P. Yang, National Nano Device Laboratories, Taiwan, R.O.C.
L.Y. Chen, United Microelectronic Corporation, Taiwan, R.O.C.
Correspondent: Click to Email
Low resistivity silicide films have received a great deal of attentions because of their applications in ULSI in recent years. Low resistivty silicides have been widely used in source/drain as contacts. They reduce both the parasitic source/drain resistance and the contact resistance. Among all the silicides, NiSi, TiSi@sub 2@, and CoSi@sub 2@ are of the lowest resistivity. TiSi@sub 2@ is currently the most common silicide used as contact metal in IC industry. However, as devices are scaled down to deep submicron dimensions, it is difficult to transform TiSi@sub 2@ from high resistivity C49 phase to low resistivity C54 phase in small dimension features owing to the lack of nucleation sites. CoSi@sub 2@ is also of low resistivity and has been a promising candidate to substitute TiSi@sub 2@ for various processing advantages. In addition, its good lattice match with Si makes it possible to grow epitaxial silicide layer on Si. High temperature sputtering deposition (HTSD) was previously found to facilitate the phase transition from C49 to C54-TiSi@sub 2@. This method also reported as a new salicide technology for deep submicron devices to reduce the complicated process steps including TiN capping layers and preamorphization of substrate. In the present study, the Co films were deposited at different temperatures from room temperature to 550@super o@ C on (001) Si using UHV sputtering cluster tools. One- and two-step annealings were performed. TEM, XRD and AES were used to examine the samples. HTSD was found to improve both the thermal stability of CoSi@sub 2@ and CoSi@sub 2@/Si interface smoothness.