Related Experiment Video
Updated: Apr 30, 2026
09:58
Fabrication of Ti3C2 MXene Microelectrode Arrays for In Vivo Neural Recording
Published on: February 12, 2020
13.3K
SELF ALIGNED TIP DEINSULATION OF ATOMIC LAYER DEPOSITED AL2O3 AND PARYLENE C COATED UTAH ELECTRODE ARRAY BASED NEURAL
Xianzong Xie1, Loren Rieth1, Sandeep Negi1
1Department of Electrical and Computer Engineering, University of Utah, Salt Lake City, UT 84112 USA.
Journal of Micromechanics and Microengineering : Structures, Devices, and Systems
|April 29, 2014
Summary
A new self-aligned process effectively deinsulates neural interface tips with alumina and Parylene C bi-layer encapsulation, improving device lifetime and performance. This method prevents micro-cracks and maintains electrical properties for reliable neural recording.
Area of Science:
- Biomaterials Science
- Neurotechnology
- Surface Engineering
Background:
- Neural interfaces, particularly Utah electrode arrays, face challenges in tip deinsulation due to complex geometries.
- Existing Parylene C insulation can lead to micro-cracks during deinsulation, impacting device reliability.
- Bi-layer encapsulation with alumina and Parylene C offers improved lifetime for neural interfaces.
Purpose of the Study:
- To develop and characterize a novel three-step self-aligned process for tip deinsulation of bi-layer encapsulated neural arrays.
- To evaluate the effectiveness of alumina and Parylene C bi-layer encapsulation in preventing micro-cracks during deinsulation.
- To assess the electrical properties and performance of deinsulated iridium oxide tips.
Main Methods:
- A three-step self-aligned deinsulation process involving laser ablation, O2 reactive ion etching, and buffered oxide etch.
- Characterization using scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy.
- Evaluation of charge injection capacity, charge storage capacity, and impedance of deinsulated iridium oxide.
Main Results:
- The developed process successfully deinsulated bi-layer encapsulated arrays without causing micro-cracks in the iridium oxide.
- Bi-layer encapsulation prevented micro-cracks during laser ablation, a common issue with Parylene-only insulation.
- Deinsulated iridium oxide with bi-layer encapsulation showed higher charge injection capacity (320 nC vs 240 nC) and similar electrochemical impedance (2.5 kΩ) compared to Parylene-only insulation.
- Consistent tip impedances (median 32 kΩ) demonstrated the effectiveness and uniformity of the self-aligned deinsulation process.
Conclusions:
- The three-step self-aligned deinsulation process is effective for alumina and Parylene C bi-layer encapsulated neural interfaces.
- Bi-layer encapsulation significantly enhances the robustness of the deinsulation process, preventing critical micro-cracks.
- The improved deinsulation leads to enhanced electrical performance, crucial for reliable neural recording and stimulation.
