International Symposium on LifeChips 2006

Si microprobe array chips for in-vivo recording of neural activity
The study of nervous system is a key problem in recent neuroscience. The analysis of the nervous system requires simultaneous recording as well as stimulation of a large number of neurons in the tissue. Many penetrating microelectrodes have been reported. However, with the previous fabrication technology, diameter of the needle has been of the order of 10-2 mm. The electrode probes are too large for electrode penetration due to the small neurons. We have proposed the penetrating microelectrode array by a selective Si growth, based on vapor-liquid-solid (VLS) growth. The Si microprobes with 2 µm in diameter and 120 µm in length, fabricated at drain region of the MOSFET have been fabricated using standard CMOS process followed by the VLS growth. The greatest merit of the device is that the microprobe array can be combined with integrated signal-processors on the same chip. For the neural applications, the electrode device needs to be combined with amplifier, filter, other analog circuits as well as digital circuits, on the same chip, improving the performance. On the other hand, for successful neural analysis, very fine needle of the electrode, each with a few microns in diameter, similar in size to neuron, and high-density electrode array, similar to the distribution of neurons, are both highly desirable. The diameter of the penetrating needle by the selective VLS growth has been dramatically reduced, compared with electrodes reported by other groups. Finally, neural recording using a carp retina is demonstrated.

Biography
Makoto Ishida was born in Hyogo, Japan, in 1950. He received the Ph.D. degree in electronics engineering from Kyoto University, Kyoto, Japan, in 1979. Since 1979 he has been at Toyohashi University of Technology, and he is a professor of electrical and electronic engineering, Director of Intelligent Sensing System Research Center, Director of Venter Business Laboratory (VBL), Leader of 21st COE program ”Intelligent Human Sensing”, and Coordinator of Japanese side for Core University Program “R&D of Advanced Semiconductor“ between Japan and Korea. He is working on development of smart microchips for human sensing including sensors and IC in electron device research center in Toyohashi University of Technology, and Si related materials and devices with epitaxial Al2O3 insulator and Si films and their device applications for advanced semiconductor devices.