In this work, we have studied thermal stability of nanoscale Ag metallization and its contact with CoSi2 in heat-treated Ag(50 nm)/W(10 nm)/Co(10 nm)/Si(100) multilayer fabricated by sputtering method. To evaluate thermal stability of the systems, heat-treatment was performed from 300 to 900 degrees C in an N-2 ambient for 30 min. All the samples were analyzed by four-point-probe sheet resistance measurement (R-s), Rutherford backscattering spectrometry (RBS), X-ray diffractometry (XRD), and atomic force microscopy (AFM). Based on our data analysis, no interdiffiusion, phase formation, and Rs variation was observed up to 500 degrees C in which the Ag layer showed a (111) preferred crystallographic orientation with a smooth surface and R-s of about 1 Omega/rectangle. At 600 degrees C, a sharp increase of R-s value was occurred due to initiation of surface agglomeration, WSi2 formation, and interdiffusion between the layers. Using XRD spectra, CoSi2 formed at the Co/Si interface preventing W silicide formation at 750 and 800 degrees C. Meantime, RBS analysis showed that in this temperature range, the W acts as a cap layer, so that we have obtained a W encapsulated Ag/CoSi2 contact with a smooth surface. At 900 degrees C, the CoSi2 layer decomposed and the layers totally mixed. Therefore, we have shown that in Ag/W/Co/Si(100) multilayer, the Ag nano-layer is thermally stable up to 500 degrees C, and formation of W-capped Ag/CoSi2 contact with R-s of 2 Omega/rectangle has been occurred at 750-800 degrees C. (c) 2005 Elsevier B.V. All rights reserved.