Aligning Silicon Nanopillar Formed in Electroless HF/H2O2 Etching through Pre-Forming Porous Layer

Tuesday, October 13, 2015: 16:40
Russell C (Hyatt Regency)
C. C. Chiang, D. Xu (National Central University), Y. C. Huang, P. C. Juan (Ming Chi University of Technology), F. S. Lo, H. Q. Hu, C. L. He (National Central University), and T. H. Lee (National Central University)
For fabricating a controllable nanopillar array structure by utilizing the metal-assisted etching technique, we created a fine porous cladding layer on the surface of bulk silicon to settle down silver nanoparticles.

Prior to metal-assisted etching process, a 10nm thick porous silicon layer was produced on the surface of a p-type, 1-10 Ohm-cm, (100) bulk silicon by HF based electrochemically etching and then rinsed by D.I. water. After spin-drying, the specimen and a same silicon specimen but without the porous layer were dipped in a solution (HF / AgNO3 / H2O) for 30 seconds for the nucleation of silver nanoparticles. The dipped specimens were then etched by HF/ H2O2/ H2O solution for forming nanopillar.

Through the observation of Field Emission Scanning Electronic Microscopy (FE-SEM), we found the pores on the surface of the porous layer could provide priority nucleation sites for silver nanoparticles. Hence, we could achieve a designed silicon nanopillar array by controlling the formation of the porous layer. After etching, the silicon specimen with the pre-forming porous layer exhibits different characteristic from the one without the layer as shown in figure.