IR Transmittance of Si/SiO 2 /Si 3 N 4 /Si Insular Structures Formed by Selective Laser Annealing

Periodic Si/SiO 2 /Si 3 N 4 /Si structures with an insular surface layer were formed by selective laser annealing. A study by Fourier infrared spectrometry in the range 2–25 μm showed a decrease in the transmittance of the insular structure formed by selective laser annealing as compared to the structure without annealing. The decrease in the transmittance coefficient may have been due to heavily doped regions of recrystallized silicon in the surface layer. An analysis of dispersion curves obtained by finite-difference time-domain (FDTD) modeling showed that 5–20-THz plasma-like oscillations could be supported in a layer of periodic highly doped silicon islands in a layer of undoped silicon. The study results were interpreted assuming that plasma-like oscillations (spoof surface plasmons) arose in the structure with an insular surface layer.