Electrochimica Acta, Vol.54, No.25, 6036-6041, 2009
Electroless deposition of NiWB alloy on p-type Si(100) for NiSi contact metallization
Recently, we have proposed a novel method to form NiSi contacts using electroless plating of Ni-alloys (NiP, NiWP, NiWB) on p-type Si(1 0 0) modified by aminopropyltriethoxysilane (APTS) activated with Pd-citrate [A. Duhin, Y. Sverdlov, Yishay Feldman, Y. Shacham-Diamand, Microelectron. Eng. 84 (2007) 2506]. In this work we focus on NiWB thin films that were formed by this method. Alkali metal free electroless plating was developed using dimethylamine-borane (DMAB) and tungstatic acid (H2WO4) as a reducing agent and a source of tungsten ions, respectively. Using this method we succeeded to receive relatively high tungsten concentration (maximum value of 19-21 at%) in the electroless deposited NiWB films with good adhesion to the Si-substrate. In this paper, the advantages of using the APTS activated with Pd-citrate for NiWB alloy deposition on the Si substrate is discussed. The chemically deposited NiWB samples were annealed for 1-2 h in vacuum (<10(-6) Tort) forming the silicide layer. The annealing temperatures were 650 degrees C for NiWB alloys. X-ray diffraction (XRD) measurement confirmed the presence of NiSi phase after annealing. In addition the WSi2 phase was formed. The results are reported and summarized. (C) 2009 Elsevier Ltd. All rights reserved.