Nickel deposition on porous silicon utilizing lasers

Thin metallic nickel deposits on porous silicon (PS) surfaces from electroless nickel plating bath have been obtained by the laser-induced photochemical metallization method. Lasers such as XeCl (λ=308 nm, τ∼15 ns), KrF (λ=248 nm, τ∼500 fs), Ti:sapphire (λ=745.5 nm, τ∼120 fs) and Q-switched Nd:YAG (λ=1064 nm, τ∼150 ns) were utilized in order to achieve direct deposition of Ni. Depending on the laser parameters, the thickness of the deposits varies from a few up to several tens of nanometers when excimer pulses are applied. Investigations using Ti:sapphire and Q-switched Nd:YAG have failed; however, no Ni deposition occurred. The high lateral resolution of the patterns (<5 μm) makes the fabricated metal structures suitable for direct applications (i.e. electrical contacts, mechanical structures as well as contact masks). The deposits were analyzed using SEM, EDX and resistance measurements. FIB and profilometry were involved to characterize the cross-section of the formed metal layers.