An implantable seven-channel silicon microelectrode was fabricated by MEMS （micro-electro-mechanical system） micromachining techniques for optic-nerve visual prosthesis applications. Theoretical analyses of noise contributed to determining the size of the exposed recording sites of the microprobe. The geometry configuration was optimized for the silicon microprobe to have enough strength and flexibility and to reduce the insertion-induced tissue trauma. Impedance test results showed that the average value of the channels was 2.3MΩ at lkHz when applied with a stimulating voltage with the amplitude of 50mVpp,which is suitable for neural signal recordings. In-vivo animal experiment showed that the recorded neural signal amplitude from the primary visual cortex was 8μV.
