Electroless deposition of Ag on Pd-activated TiN/p-Si(100) substrate

Nano-thick Ag films were electrolessly deposited on TiN/p-Si(100) substrates. The substrates were prepared by sputtering TiN on p-Si( 100) wafers. An activation process of the substrates was performed by immersing the substrates in a solution of 0.0019 moL L-1 PdCl2 + 0.45 moL L-1 HF+ 8.7 moL L-1 acetic acid+ 0.036 moL L-1 HCl so as to obtain the Pd seed layer. The general composition of the electroless Ag bath was 0.0032 moL L-1 AgNO3 + 2.24 moL L-1 NH3 + 0.56 moL L-1 acetic acid+ 0.1 moL L-1 NH2NH2 at pH 10.2. The morphologies of the Pd seed layer and the Ag films were characterized by atomic force microscopy (AFM). The effect of the Pd activation on electroless Ag deposition was tested by open circuit potential with time technology (OCP-t). For comparison, the morphology of the films deposited by electro-chemical deposition on the substrates was also studied by AFM.