2019 Lecture: SEA – The Large-Count High-Density 3D Probe for Neural Recording - Professor Khalil Najafi, University of Michigan


Accurate brain mapping and deciphering the underlying neural circuits requires simultaneous high-resolution spatio-temporal recording and stimulation of neurons in various layers and areas of the brain. Conventional penetrating micro electrode arrays (MEAs) are limited to, at best, a few 100-1000 electrodes with limited volumetric 3D spatial resolution. This is mainly due to the limitations
of fabrication technologies and available designs and materials for making such probes. Many applications require a 3D dense array with many electrodes with arbitrary geometrical distribution and shape. This talk will present a new silicon-based microfabrication technology to create ultra-high-density, large-count, 3D arrays of sharp, long, and narrow silicon microelectrode needle arrays with user-defined needle length, width, density, shape and distribution. The technology is based on refilling ultra-deep ultra-high aspect-ratio holes in a silicon substrate with deposited layers to form thousands and eventually millions of electrodes. Using this technology, we have fabricated millimetre-long (1.2mm), narrow (10-20μm diameter), sharp (submicron tip size), high-density (400 electrodes/mm2) high-count (5000+) electrode arrays. 


Professor Najafi is the Schlumberger Professor of Engineering in the ECE dept. at Univ. of Michigan. He served as the Peter and Evelyn Fuss Chair of ECE Dept. during 2008 to 2018, the Director of the Solid-State Electronics Lab from 1998-2005, the deputy director of the NSF ERC on Wireless Integrated Microsystems from 2000- 2009, and the director of NSF’s National Nanotechnology Infrastructure Network 2004-2015.

Professor Najafi has been active in the field of solid-state sensors and actuators for 35 years. His research interests include: micromachining technologies, MEMS; analogue integrated circuits; implantable biomedical microsystems; hermetic and vacuum packaging; and low power wireless sensing/actuating systems; inertial sensing systems. He received the IEEE Daniel E. Noble Technical Field Award in 2015 and the IEEE Sensors Council Technical Achievement Award in 2013. He is a Fellow of the IEEE and the AIBME.

First published: 11 July 2019