Influence of surfactant on aperture of photo-electro-chemical etching for silicon microchannel plate

The influence of several surfactants in electrolyte during silicon electrochemical etching was reported in this paper. The morphologies of macroporous silicon arrays in n-type silicon are strongly influenced by the chemical nature of these additives. Conventional solvents (HF-Ethanol) with cationic (hexadecyl trimethyl ammonium chloride), non-ionic (Triton-X100) and anionic (sodium alpha-olefin sulfonate) surfactants were experimented respectively. Prominent differences in microchannel morphologies and apertures were observed depending on the nature of the additive. The different behaviors of the additives during the electrochemical etching process were linked to the physical properties of the additives. We found the electric double layer model of the reaction interface partially to explain these results. However, not only the morphology of the microchannel but also the degree of electrochemical reaction is affected by surfactant. The anionic surfactant is more suitable for the preparation of silicon microchannel plate with high aspect ratio and pore size uniform. The depth of microchannels etched by photoelectrochemical etching silicon with anionic surfactant is 264 μm, and the pore size is 2 μm.