Control Technology of Channel Dimension in the Photo-electro-Chemical Etching for Silicon Microchannel Arrays

The application fields of high aspect ratio Si microchannel arrays have increased considerably,for example, photonic crystals,Si microchannel plates,MEMS devices and so on.Photo-electrochemical etching (PEC) of Si microchannel arrays was researched,and the control technology of channel dimension were studied in detail.The current-voltage curve of an n-type silicon wafer was presented in aqueous HF.The critical current density JPS was discussed and an indirectly method was presented to measure the relation of JPS at the pore tip and etching time.The influence of dark current density on the characteristic of etching was researched.The relation of dark current density and the etching time was presented.The channel dimensional control was realized by changing the etching current density according to the JPS and dark current density.The perfect Si micro-channel arrays structure with the pore depth of 300 m,the pore size of 3 m and the aspect ratio of 100 was obtained.