Oliver Paul

Department of Microsystems Engineering (IMTEK), University of Freiburg, Freiburg, DE

Associated articles

TBME, Featured Articles
CMOS-compatible, Flexible, Intracortical Neural Probes
Flexible intracortical neural probes elicit a lower tissue response compared to rigid implants. However, silicon-based neural probes incorporating complementary metal-oxide-semiconductor (CMOS) circuitry offer improved scalability and functionality. We describe a novel neural implant combining short, needle-like CMOS-based probe tips with flexible polyimide cables. Ultra-thin shuttles enable their complete implantation into brain tissue. An optimized cable fabrication process based on ion beam and plasma etching increases line and pad density, thus minimizing the bond area between cable and probe tip to widths of 100 µm. The synergetic approach surpasses the limitations of each individual probe technology and should be considered in future developments... Read more
TBME, Featured Articles
Compact Optical Neural Probes with up to 20 Integrated Thin-Film μLEDs Applied in Acute Optogenetic Studies
Slender silicon-based optical probes comprising up to 20 thin-film micro light-emitting diodes (µLEDs) are realized as compact devices for optogenetic research. The μLEDs are structured on GaN-on-sapphire and transferred onto silicon using a wafer-level bonding and laser lift-off process. This technology allows processing the GaN layer stack from both sides, thereby maximizing the µLED efficiency to an emittance of 56 mWmm−2 at 5 mA. The thermal characterization of the optical probes reveals a temperature increase of up to 1.5 K. Acceptable neuronal responses are elicited at radiant flux values between 1.36 μW and 17.5 μW, successfully demonstrating layer-specific cortex stimulation... Read more