Design Method of 3-D Active Silicon Neural Microelectrode Biosensor Based on MEMS Technology

This paper discussed the design method of a 3-D 32 sites active silicon microelectrode biosensor. Base on the MEMS technology, a new microstructure of active neural recording arrays system is presented, where two 2-D probes, two integrate circuits as well as two spacers are microassambled on a 5×7 mm2 silicon platform. A theoretical measurement model for measuring the neural signal by the silicon microelectrode was proposed based on the structure and fabrication process of a single-shank probe. The on-chip unity-gain bandpass amplifier has an overall gain of 42dB over a bandwidth from 60Hz to 10 kHz; the dc-baseline stability circuit with high input resistance above 30MΩ to guarantee a cutoff frequency below 100 Hz. The circuit works in two models: stimulating or recording. The conversion of the models depends on the outside stimulating control signal. The method of determining the dimensional parameters values of the probe shank is discussed in the following three aspects: the structure of pallium, efficient, coupled interconnects noise and strength characteristic of neural probe. The design criterion is to minimize the size of the neural probe when the probe has enough stiffness to pierce the endocranium.