SI MICRO PROBE AND SIO 2 MICRO TUBE ARRAY INTEGRATED WITH NMOSFETS Kuniharu Takei, Takahiro Kawashima, Hidekuni Takao, Kazuaki Sawada, and Makoto Ishida Transducers’07 Presenter ： Wen-Fan Liao ID ： g Instructor ： Cheng-Hsien Liu

Outline  Introduction  Process  Results  Conclusion  References

Introduction  Neural activity recording is important to analyze neural networks  Recording site and invasiveness are issues  Proposed micro probes and tube array for neural penetrating devices fabricated by Vapor-Liquid- Solid (VLS) method

Process  Process sequence of probe, tube with on-chip MOSFETs

Process  SEM images of Si micro probe before and after deposition of SiO 2 by PECVD; (a) Before deposition, (b) After deposition

Process  Fabricated Si micro probe and SiO 2 micro tube array with on-chip MOSFETs Diameter and length for Si micro probe are 2μm and 30μm respectively. SiO 2 tube is 2.7μm in inner diameter, 3.6μm in outer diameter, and 29μm in length

Results  SiO 2 thickness by PECVD as a function of deposition time

Results  Microscope images of maximum bending the probe and tube before breaking Probe diameter : 3μm Tube diameter : 4μm Maximum displacements of Si micro probe and SiO 2 micro tube are 3.75μm and 3.25μm respectively

Results  FEM simulation results: (1) shows the available added pressure as a fuction of displacement, (b) indicates the maximum stress as a function of added pressure 1.95MPa 2.05MPa 3.0GPa 3.2GPa

Results  Estimated capable penetration pressure at the maximum stress for the micro probe and tube 1750MPa 400MPa

Results  Photographs and schematic images for which probes and tubes were penetrated (1,2) and extracted (3) from the gelatin

Conclusion  This work reports the development of Si micro probe and SiO 2 micro tube array with on-chip MOSFETs for a neural recording device  This device is expected to be suitable for analysis of neural behavior with low invasiveness, which can be applied in neuron science or other applications

References  Kuniharu Takei, Takahiro Kawashima, Hidekuni Takao, Kazuaki Sawada, and Makoto Ishida, “SI MICRO PROBE AND SIO 2 MICRO TUBE ARRAY INTEGRATED WITH NMOSFETS,” Transducers’07, Lyon, France, June 2007  Kuniharu Takei, Takahiro Kawashima, Kazuaki Sawada, and Makoto Ishida, “MECHANICAL PROPERTIES OF MICRO PROBE AND TUBE ARRAY FOR NEURAL PENETRATING DEVICES,” Engineering in Medicine and Biology Society, EMBS th Annual International Conference of the IEEE  neuroscience.ppt

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