عنوان مقاله [English]
in this paper, a low-cost Ni/Cu structure as an ohmic contact was fabricated on multicrystalline n+-Si by using electrochemical method and the electrical resistivity of the contact was optimized. Ni was deposited on substrates by two methods: electroless plating and electroplating. After Ni electroplating, samples were annealed at various temperature and then an electroplated copper layer was formed on Ni film in order to reduce the sheet and contact resistance with using an ultrasonic system one can obtain a film with the lower surface roughness and the higher quality. Post treatments of the coated Ni improved the crystalline structure of the electroplated layer. SEM, XRD, and EDX analyses were used to investigate the surface morphology, structure and composition of deposited films. The surface roughness was investigated by profile stylus DEKTAK. Contact resistance of the Si/Ni/Cu structure was measured using the Transmission Line Model (TLM) method. Results demonstrate that specific contact resistance for the electroless plated Ni/Cu structure is 8.9×10-5 Ωcm2, while an optimum specific contact resistance of 2.2 ×10-5 Ωcm2 is obtained for structure with electroplated Ni layers.