Local Schottky contacts of embedded Ag nanoparticles in Al₂O₃/SiN_x:H stacks on Si: a design to enhance field effect passivation of Si junctions

This paper describes an original design leading to the field effect passivation of Si n⁺-p junctions. Ordered Ag nanoparticle (Ag-NP) arrays with optimal size and coverage fabricated by means of nanosphere lithography and thermal evaporation, were embedded in ultrathin-Al₂O₃/SiN_x:H stacks on the top of implanted Si n⁺-p junctions, to achieve effective surface passivation. One way to characterize surface passivation is to use photocurrent, sensitive to recombination centers. We evidenced an improvement of photocurrent by a factor of 5 with the presence of Ag NPs. Finite-difference time-domain (FDTD) simulations combining with semi-quantitative calculations demonstrated that such gain was mainly due to the enhanced field effect passivation through the depleted region associated with the Ag-NPs/Si Schottky contacts. (paper)