The formation of metallic silicides of titanium, yttrium, iron, molybdenum and tungsten using metal vapour vacuum arc implantation

The formation of metallic silicides was studied using implantation into Si with ions of Ti, Y, Fe, Mo and W produced by a metal vapour vacuum arc ion source. The electrical properties were measured by four-probe and spread-resistance probe devices. The resistivities are from tens to hundreds of micro-ohm centimetres for the implantation of these ions. The resistivity of Ti-, Y- and Fe-implanted layers decreased obviously with increasing ion flux. In contrast, the lowest resistivity is found for Mo and W implantations at 50 mu Acm exp -2 . The glossy surface changes into a rough surface and the resistivity increases, if the ion flux of Mo and W is larger than 75 mu Acm exp -2 . The silicide phases were distinguished by X-ray diffraction and Rutherford backscattering spectrometry. The metallic silicides TiSi, TiSi sub 2 , YSi, YSi sub 2 , FeSi, FeSi sub 2 , MoSi sub 2 and WSi sub 2 were fully formed if the ion flux was as high as 50 mu Acm exp -2 . The surface atomic ratio was about 40%-60% for Ti, Y and Fe, and 20%-25% for Mo and W, if implanted doses of (3-5)mult10 exp 17 cm exp -2 were used. The distribution depth of the silicides was about 30-80nm. The new process technique is suitable and can be employed for shallow junction technologies of very-large-scale integration. Copyright 1994 Elsevier Science S.A. All rights reserved.