AVS 46th International Symposium
    Surface Science Division Tuesday Sessions
       Session SS-TuP

Paper SS-TuP11
A Study of Boron Effects on the Reaction of Co and SiGe at Various Temperatures

Tuesday, October 26, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: H.J. Huang, National Chiao Tung University, Taiwan, R.O.C.
Authors: H.J. Huang, National Chiao Tung University, Taiwan, R.O.C.
K.M. Chen, National Chiao Tung University, Taiwan, R.O.C.
T.C. Chang, National Nano Device Laboratory, Taiwan, R.O.C.
G.W. Huang, National Nano Device Laboratory, Taiwan, R.O.C.
L.P. Chen, National Nano Device Laboratory, Taiwan, R.O.C.
C.Y. Chang, National Chiao Tung University, Taiwan, R.O.C.
Correspondent: Click to Email
The boron effects on Co and SiGe interfacial reaction were studied with RTA from 500°C to 1000°C. The undoped and in-situ boron-doped strained Si@sub 0.91@Ge@sub 0.09@, Si@sub 0.85@Ge@sub 0.15@ layers were prepared at 550°C by ultra-high vacuum chemical vapor deposition system for silicidation. The resulting films were characterized by sheet resistance measurement, Auger electron spectroscopy, X-ray diffractometry, high resolution X-ray diffractometry, secondary ion mass spectroscopy, scanning electron microscopy, and transmission electron microscopy. Co(Si@sub 1-y@Ge@sub y@) cubic structure was formed from 500°C to 700°C RTA with different Ge content. For the boron-doped sample, Ge content (y = 0.064, 0.054) in Co(Si@sub 1-y@Ge@sub y@) was less than undoped sample ( y= 0.12, 0.11) after 500°C RTA, which can be discovered by X-ray diffraction. This implied that boron atoms retarded the incorporation of Ge into the Co(Si@sub 1-y@Ge@sub y@) ternary phase. It also led to large piled-up of Ge at the reaction interface. On the other hand, according to the X-ray rocking curve, boron-doped sample led to less relaxation of strained SiGe layer. Furthermore, from sheet resistance measurement, the formation of CoSi@sub 2@ was a little slower in boron doped sample than in undoped sample. This may be due to the decrease of Co diffusivities, which was caused by the boron accumulation at the Co/SiGe reaction interface. At temperature above 800°C, CoSi@sub 2@ was formed and the underlying SiGe layer was almost totally consumed. From the AES and TEM analyses, Ge segregation to the surface and the CoSi@sub 2@ grain boundary was observed.