Role of local microchemistry and surface structure in electrical resistivity of 50 nm electroless films Ag-W-oxygen

We studied electroless 50 nm films Ag (0.2-1.2 at.% W) which contain also some oxygen and were deposited onto SiO2/Si substrate. The films showed better corrosion resistance and hardness than pure Ag, but rather high electrical resistivity p which decayed fast after annealing at T >=, 100 degrees C [Y. Shacham-Diamand, A. Inberg, Y. Sverdlov, N. Croitoru, J. Electrochem. Soc. 147 (2000), 3345-3349; A. Inberg, V. Bogush, N. Croitoru, V. Dubin, Y. Shacham-Diamand, J. Electrochem. Soc. 150 (2003) C285-C291; V. Bogush, E. Ginsburg, A. Inberg, N. Croitoru, V. Dubin, Y. Shacham-Diamand, in: G.W. Ray et al. (Eds.), Advanced Metallization Conference 2003 (AMC 2003), MRS, Warrendale, PA, 2004, pp. 607-611; E.E. Glickman, A. Inberg, V. Bogush, N. Croitoru, Y. Shacham-Diamand, Microelectron. Eng. 70 (2003) 495-500; E.E. Glickman, A. Inberg, V. Bogush, G. Aviram, N. Croitoru, Y. Shacham-Diamand, Microelectron. Eng. 76 (2004) 182-189]. Application of XPS, HRTEM/EELS and HRSEM/EDS made it possible to reveal that open porosity, co-segregation of W and oxygen and formation of non-metallic phases Ag2W2O7 and AgO at the grain/cluster of grains interfaces are the major factors which contributed to high p in the as-deposited films. AFM data treated in terms of fractal scaling theory suggest that surface tension driven sintering in the course of annealing at 125 degrees C is responsible for the resistivity decay, while HRTEM shows that grain size does not change. (c) 2005 Elsevier B.V. All rights reserved.