Ion Beam Synthesis of Buried Co x Ni 1-x Si 2 Layers in Silicon
- PDF / 719,522 Bytes
- 6 Pages / 414.72 x 648 pts Page_size
- 28 Downloads / 219 Views
M.F. WU1, J. DE WACHTER 2 , A.-M. VAN BAVEL 2 , H. PATTYN 2 , G. LANGOUCHE 2 , 4 4 3 3 J. VANHELLEMONT , H. BENDER , K. TEMST , B. WUYTS AND
Y. BRUYNSERAEDE
4
1 Department of Technical Physics, Peking University, Beijing, PR China, and Instituut voor Kern- en Stralingsfysica, University of Leuven, B-3001 Leuven, Belgium 2 Instituut voor Kern- en Stralingsfysika, University of Leuven, B-3001 Leuven, Belgium 3 IMEC, Kapeldreef 75, B-3001 Leuven, Belgium 4 Laboratorium voor Vaste-Stoflysika en Magnetisme, University of Leuven, B-3001 Leuven, Belgium
ABSTRACT Heteroepitaxial CoxNi Il.xSi 2 layers with good crystalline quality have been formed by ion beam synthesis. Rutherford Backscattering (RBS) - Channeling, Auger Electron Spectroscopy (AES), Transmission Electron Microscopy (TEM) and X-Ray Diffraction (XRD) have been used to study the buried layers. For a sample with x=0.66, we found that this ternary silicide layer contains 11% type B and 89 % type A orientation. The TEM investigation reveals that the type B component is mainly located at the interfaces with a thickness of a few monolayers. XRD studies show that the strain of the type B component is smaller than that of the type A component, and this is probably the reason for such a unique distribution of the type B component in the epilayer.
FORMATION OF THE Co.Nil.xSi 2 LAYERS Ion beam synthesis (IBS) has already been used successfully to form continuous buried or surface CoSi 2 epitaxial layers with very good crystalline quality and electrical transport properties in Si substrates [1-4]. NiSi 2 is another interesting silicide with properties similar to CoSi 2. Its epitaxial growth on a Si substrate using conventional ultrahigh vacuum techniques has been extensively studied. However both CoSi2 and NiSi 2 have typical advantages and disadvantages for practical applications in microelectronics. Therefore, it has been suggested that the ternary silicides might be a better choice than the pure disilicides [5]. Regarding the 159 Mat. Res. Soc. Symp. Proc. Vol. 320. ©1994 Materials Research Society
different crystal orientation of UHV-prepared NiSi 2 and CoSi2 layers on Si(1 11) and of CoSi2 layers prepared by lBS and CoSi2 layers formed with UHV-methods [5-9], it is interesting to study the various properties of lBS-formed epitaxial CoxNil-xSi2 layers as a function of x. For carrying out such orientation, strain, resistivity and thermal stability studies, high quality CoxNil-xSi2 layers have to be prepared first. This is more difficult than the formation of CoSi 2 layers by lBS [8]. An ion source loaded with CoCI2 and NiCI2 at the same time can produce Co and Ni 58 ions. A Si(1 11) substrate has been implanted with 59 Co+ followed by Ni+ ions with a given dose ratio of x/(1-x). Several implantations have been performed at 3000 C with 90 keV to a fixed dose of 1.1x10 17 /cm 2 with x varying between 0 and 1. Vacuum furnace (=- 10-7 Torr) annealing has been used to anneal the implanted samples. The highest quality ternary silicide layer (Co 0 .66 Ni0 .34 Si2 ) ha
Data Loading...
