New type of dual macro and nano fractal structure of reaction induced vapor phase stain etched porous silicon

Abstract

A comprehensive study of morphology of Reaction-Induced Vapor Phase Stain Etched porous silicon was performed in order to inspect samples for fractal structure and to estimate their potential for sensing applications. A new dual fractal structure is found in porous silicon layer obtained by Reaction-Induced Vapor Phase Stain Etch. The layer consists of two superposed fractal macro-and nanostructures. The macrostructure is formed due to the condensation of drops while the nanostructure is caused by the chemical reactions of the vapor molecules with the silicon surface. A comparison with morphology of porous silicon prepared by Liquid Phase Stain Etch is also presented.

MEMS composite porous silicon/polysilicon cantilever sensor for enhanced triglycerides biosensing

“…This stru cture was not observed on the as grown polysilicon before the release process of the cantilevers and can be a consequence of the long 90 min etching of the sacrificial oxide in buffered HF required for For very short etching periods (2-3sec), a uniform nanostructured surface morphology with regular round pores of 5-7 nm is formed (Fig 3b). For longer etching times, the porous polysilicon layer shows a dual fractal macro and nanostructure (Fig.3c) as was found for porous silicon formed by vapor phase etch of crystalline silicon [16].The ma crostructure reflects the condensation of drops from the reactive vapor while the nanostructure originates from the local reactions of vapor molecules with silicon resulting in nanoscale morphology. The macro-pore size reached 100-200 nm resulting in the additional increase in surface area.…”

Composite porous silicon-crystalline silicon cantilevers for enhanced biosensing

“…2 shows the general view of a microcantilever array before and after fabrication of porous silicon layer. The dual macro and nano fractal structure has been reported in [28]. The macrostructure reflects the condensation of drops giving the round shaped features.…”

NEMS/MEMS cantilever-based biosensors: addressing the open issues

“…5b) superposed structure of the porous layer. The dual macro and nano fractal structure has been reported in [59]. The macrostructure reflects the condensation of drops giving the round shaped features.…”