scholarly journals Fabrication of free-standing silicon carbide on silicon microstructures via massive silicon sublimation

2020 ◽  
Vol 38 (6) ◽  
pp. 062202
Author(s):  
Mojtaba Amjadipour ◽  
Jennifer MacLeod ◽  
Nunzio Motta ◽  
Francesca Iacopi
Keyword(s):  
Silicon Carbide ◽  
Free Standing ◽  
Silicon Microstructures

scholarly journals Origin of Doping in Quasi-Free-Standing Graphene on Silicon Carbide

2012 ◽  
Vol 108 (24) ◽  
Author(s):  
J. Ristein ◽  
S. Mammadov ◽  
Th. Seyller
Keyword(s):  
Silicon Carbide ◽  
Free Standing

Fabrication of free-standing porous silicon microstructures

2007 ◽  
Vol 17 (7) ◽  
pp. S164-S167 ◽  
Author(s):  
O Garel ◽  
C Breluzeau ◽  
E Dufour-Gergam ◽  
A Bosseboeuf ◽  
B Belier ◽  
...  
Keyword(s):  
Porous Silicon ◽  
Free Standing ◽  
Silicon Microstructures

SiC for Biomedical Applications

2016 ◽  
Vol 858 ◽  
pp. 1010-1014 ◽  
Author(s):  
Stephen E. Saddow ◽  
Christopher L. Frewin ◽  
Fabiola Araujo Cespedes ◽  
Marioa Gazziro ◽  
Evans Bernadin ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Biomedical Applications ◽  
Glucose Monitoring ◽  
Wide Band ◽  
Neural Interfaces ◽  
Free Standing ◽  
Wide Band Gap ◽  
Custom Made ◽  
Biological World ◽  
Machine Interface

Silicon carbide is a well-known wide-band gap semiconductor traditionally used in power electronics and solid-state lighting due to its extremely low intrinsic carrier concentration and high thermal conductivity. What is only recently being discovered is that it possesses excellent compatibility within the biological world. Since publication of the first edition of Silicon Carbide Biotechnology: A Biocompatible Semiconductor for Advanced Biomedical Devices and Applications five years ago [1], significant progress has been made on numerous research and development fronts. In this paper three very promising developments are briefly highlighted – progress towards the realization of a continuous glucose monitoring system, implantable neural interfaces made from free-standing 3C-SiC, and a custom-made low-power ‘wireless capable’ four channel neural recording chip for brain-machine interface applications.

Free‐standing silicon microstructures fabricated by laser chemical processing

1993 ◽  
Vol 73 (11) ◽  
pp. 7864-7871 ◽  
Author(s):  
Helena Westberg ◽  
Mats Boman ◽  
Stefan Johansson ◽  
Jan‐Åke Schweitz
Keyword(s):  
Chemical Processing ◽  
Free Standing ◽  
Silicon Microstructures

scholarly journals Fabrication of a Monolithic Implantable Neural Interface from Cubic Silicon Carbide

Micromachines ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 430 ◽  
Author(s):  
Mohammad Beygi ◽  
John T. Bentley ◽  
Christopher L. Frewin ◽  
Cary A. Kuliasha ◽  
Arash Takshi ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Microelectrode Array ◽  
Electrochemical Impedance ◽  
Chemical Vapor ◽  
Silicon On Insulator ◽  
Free Standing ◽  
Multiple Materials ◽  
Materials Used ◽  
Cubic Silicon Carbide

One of the main issues with micron-sized intracortical neural interfaces (INIs) is their long-term reliability, with one major factor stemming from the material failure caused by the heterogeneous integration of multiple materials used to realize the implant. Single crystalline cubic silicon carbide (3C-SiC) is a semiconductor material that has been long recognized for its mechanical robustness and chemical inertness. It has the benefit of demonstrated biocompatibility, which makes it a promising candidate for chronically-stable, implantable INIs. Here, we report on the fabrication and initial electrochemical characterization of a nearly monolithic, Michigan-style 3C-SiC microelectrode array (MEA) probe. The probe consists of a single 5 mm-long shank with 16 electrode sites. An ~8 µm-thick p-type 3C-SiC epilayer was grown on a silicon-on-insulator (SOI) wafer, which was followed by a ~2 µm-thick epilayer of heavily n-type (n+) 3C-SiC in order to form conductive traces and the electrode sites. Diodes formed between the p and n+ layers provided substrate isolation between the channels. A thin layer of amorphous silicon carbide (a-SiC) was deposited via plasma-enhanced chemical vapor deposition (PECVD) to insulate the surface of the probe from the external environment. Forming the probes on a SOI wafer supported the ease of probe removal from the handle wafer by simple immersion in HF, thus aiding in the manufacturability of the probes. Free-standing probes and planar single-ended test microelectrodes were fabricated from the same 3C-SiC epiwafers. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were performed on test microelectrodes with an area of 491 µm2 in phosphate buffered saline (PBS) solution. The measurements showed an impedance magnitude of 165 kΩ ± 14.7 kΩ (mean ± standard deviation) at 1 kHz, anodic charge storage capacity (CSC) of 15.4 ± 1.46 mC/cm2, and a cathodic CSC of 15.2 ± 1.03 mC/cm2. Current-voltage tests were conducted to characterize the p-n diode, n-p-n junction isolation, and leakage currents. The turn-on voltage was determined to be on the order of ~1.4 V and the leakage current was less than 8 μArms. This all-SiC neural probe realizes nearly monolithic integration of device components to provide a likely neurocompatible INI that should mitigate long-term reliability issues associated with chronic implantation.

scholarly journals Silicon Carbide and MRI: Towards Developing a MRI Safe Neural Interface

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 126
Author(s):  
Mohammad Beygi ◽  
William Dominguez-Viqueira ◽  
Chenyin Feng ◽  
Gokhan Mumcu ◽  
Christopher Frewin ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Brain Tissue ◽  
High Field ◽  
Neural Interface ◽  
Image Artifacts ◽  
Mri Imaging ◽  
Neural Implants ◽  
Free Standing ◽  
High Field Mri ◽  
Sic Films

An essential method to investigate neuromodulation effects of an invasive neural interface (INI) is magnetic resonance imaging (MRI). Presently, MRI imaging of patients with neural implants is highly restricted in high field MRI (e.g., 3 T and higher) due to patient safety concerns. This results in lower resolution MRI images and, consequently, degrades the efficacy of MRI imaging for diagnostic purposes in these patients. Cubic silicon carbide (3C-SiC) is a biocompatible wide-band-gap semiconductor with a high thermal conductivity and magnetic susceptibility compatible with brain tissue. It also has modifiable electrical conductivity through doping level control. These properties can improve the MRI compliance of 3C-SiC INIs, specifically in high field MRI scanning. In this work, the MRI compliance of epitaxial SiC films grown on various Si wafers, used to implement a monolithic neural implant (all-SiC), was studied. Via finite element method (FEM) and Fourier-based simulations, the specific absorption rate (SAR), induced heating, and image artifacts caused by the portion of the implant within a brain tissue phantom located in a 7 T small animal MRI machine were estimated and measured. The specific goal was to compare implant materials; thus, the effect of leads outside the tissue was not considered. The results of the simulations were validated via phantom experiments in the same 7 T MRI system. The simulation and experimental results revealed that free-standing 3C-SiC films had little to no image artifacts compared to silicon and platinum reference materials inside the MRI at 7 T. In addition, FEM simulations predicted an ~30% SAR reduction for 3C-SiC compared to Pt. These initial simulations and experiments indicate an all-SiC INI may effectively reduce MRI induced heating and image artifacts in high field MRI. In order to evaluate the MRI safety of a closed-loop, fully functional all-SiC INI as per ISO/TS 10974:2018 standard, additional research and development is being conducted and will be reported at a later date.

Hardness and Young's modulus of amorphous a-SiC thin films determined by nanoindentation and bulge tests

1994 ◽  
Vol 9 (1) ◽  
pp. 96-103 ◽  
Author(s):  
M.A. El Khakani ◽  
M. Chaker ◽  
A. Jean ◽  
S. Boily ◽  
J.C. Kieffer ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Silicon Carbide ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Chemical Vapor ◽  
Free Standing ◽  
Film Composition ◽  
Sputtering Deposition ◽  
Sic Films

Due to its interesting mechanical properties, silicon carbide is an excellent material for many applications. In this paper, we report on the mechanical properties of amorphous hydrogenated or hydrogen-free silicon carbide thin films deposited by using different deposition techniques, namely plasma enhanced chemical vapor deposition (PECVD), laser ablation deposition (LAD), and triode sputtering deposition (TSD). a-SixC1−x: H PECVD, a-SiC LAD, and a-SiC TSD thin films and corresponding free-standing membranes were mechanically investigated by using nanoindentation and bulge techniques, respectively. Hardness (H), Young's modulus (E), and Poisson's ratio (v) of the studied silicon carbide thin films were determined. It is shown that for hydrogenated a-SixC1−x: H PECVD films, both hardness and Young's modulus are dependent on the film composition. The nearly stoichiometric a-SiC: H films present higher H and E values than the Si-rich a-SixC1−x: H films. For hydrogen-free a-SiC films, the hardness and Young's modulus were as high as about 30 GPa and 240 GPa, respectively. Hydrogen-free a-SiC films present both hardness and Young's modulus values higher by about 50% than those of hydrogenated a-SiC: H PECVD films. By using the FTIR absorption spectroscopy, we estimated the Si-C bond densities (NSiC) from the Si-C stretching absorption band (centered around 780 cm−1), and were thus able to correlate the observed mechanical behavior of a-SiC films to their microstructure. We indeed point out a constant-plus-linear variation of the hardness and Young's modulus upon the Si-C bond density, over the NSiC investigated range [(4–18) × 1022 bond · cm−3], regardless of the film composition or the deposition technique.

Structural evolution of free-standing 2D silicon carbide upon heating

2020 ◽  
Vol 74 (6) ◽  
Author(s):  
Tue Minh Le Nguyen ◽  
Vo Van Hoang ◽  
Hang T. T. Nguyen
Keyword(s):  
Silicon Carbide ◽  
Structural Evolution ◽  
Free Standing
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