3C-SiC on Si: A bio- and hemo-compatible material for advanced nano-bio devices

Saddow, Stephen E.; Frewin, C. L.; Nezafati, Maysam; Oliveros, Alexandra; Afroz, Shamima; Register, Joseph; Reyes, M.; Thomas, Sylvia

doi:10.1109/nmdc.2014.6997419

Cited by 16 publications

(17 citation statements)

References 15 publications

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“…The plasma field frequency was set to 13.56 MHz, substrate temperature to 250 °C, and pressure to 900 mTorr. Silane (SiH 4 ) and Methane (CH 4 ) were used as the reactive gas species at flow rates of 360 sccm and 12 sccm, respectively [ 25 ]. Argon (Ar) was used as the carrier gas with a flow rate of 500 sccm.…”

Section: Methodsmentioning

confidence: 99%

“…Our group believes an alternative material strategy may address both issues simultaneously. The device would be constructed exclusively of one material which has a demonstrated track record of physical robustness, chemical inertness, and a great degree of biological tolerance: crystalline silicon carbide (SiC) [ 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. Additionally, the amorphous form of SiC ( a -SiC) has also been demonstrated as an effective insulating coating which does not take up water and is very compatible with neural cells [ 25 , 32 , 33 ].…”

Section: Introductionmentioning

confidence: 99%

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Demonstration of a Robust All-Silicon-Carbide Intracortical Neural Interface

Bernardin

Frewin²,

Everly³

et al. 2018

Micromachines

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Intracortical neural interfaces (INI) have made impressive progress in recent years but still display questionable long-term reliability. Here, we report on the development and characterization of highly resilient monolithic silicon carbide (SiC) neural devices. SiC is a physically robust, biocompatible, and chemically inert semiconductor. The device support was micromachined from p-type SiC with conductors created from n-type SiC, simultaneously providing electrical isolation through the resulting p-n junction. Electrodes possessed geometric surface area (GSA) varying from 496 to 500 K μm2. Electrical characterization showed high-performance p-n diode behavior, with typical turn-on voltages of ~2.3 V and reverse bias leakage below 1 nArms. Current leakage between adjacent electrodes was ~7.5 nArms over a voltage range of −50 V to 50 V. The devices interacted electrochemically with a purely capacitive relationship at frequencies less than 10 kHz. Electrode impedance ranged from 675 ± 130 kΩ (GSA = 496 µm2) to 46.5 ± 4.80 kΩ (GSA = 500 K µm2). Since the all-SiC devices rely on the integration of only robust and highly compatible SiC material, they offer a promising solution to probe delamination and biological rejection associated with the use of multiple materials used in many current INI devices.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Demonstration of a Robust All-Silicon-Carbide Intracortical Neural Interface

Bernardin

Frewin²,

Everly³

et al. 2018

Micromachines

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“…Helium (He), with a flow rate of 700 sccm, was used as the carrier gas. The RF power was set to 200 W, substrate temperature to 300 °C, and pressure to 1100 mTorr [37,38]. Following photoresist patterning using AZ 15nXT-450 CPS negative photoresist (Microchemicals GmbH), a reactive ion etch (RIE; PlasmaTherm) was run for 210 s to open windows in the a -SiC film for the electrode sites.…”

Section: Methodsmentioning

confidence: 99%

Fabrication of a Monolithic Implantable Neural Interface from Cubic Silicon Carbide

et al. 2019

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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.

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“…1). The Si material, which can be made by the bonding process on top of SiC [11, 12], is used to form the channel and ohmic contact for the source electrode. When VDMOS structure is turned off, the highest electric field is produced at the interface of the P‐base and N‐type drift region (area A in Fig.…”

Section: Device Structure and Descriptionmentioning

confidence: 99%

SiC/Si heterojunction VDMOS breaking silicon limit by breakdown point transfer technology

Duan

Zhao

et al. 2018

Micro & Nano Letters

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An innovative semiconductor power vertical double-diffused MOSFET (VDMOS) is proposed for the first time with the SiC/Si heterojunction at the P-base and N-drift region (called for SiC/Si VDMOS), which improves the trade-off between the breakdown voltage (BV) and specific on-resistance (R on,sp). The 'soft' Si material has been combined with the 'hard' SiC material to play their own advantages for SiC/Si VDMOS. The Si has been formed above the 6H-SiC substrate to make up the channel and source electrode, and the 6H-SiC is underneath the P-base to form the SiC/Si heterojunction. The novel terminal technology of breakdown point transfer has been advanced for the first time and applied to SiC/Si VDMOS, which transfers the breakdown point of SiC/Si VDMOS and improve the BV compared with Si VDMOS. The simulated results have been shown that the optimised BV of proposed SiC/Si VDMOS is increased from 226 to 578 V compared with the conventional Si VDMOS with the same drift region length, which is because the breakdown point is transferred from the higher electric field area with the maximum curvature radius to the low electric field area. The simulated R on,sp of SiC/Si VDMOS is 17.4 mΩ•cm 2 with the BV of 578 V, which is lower than that of 41.01 mΩ•cm 2 with the BV of 226V in Si VDMOS. The silicon limit relationship has been broken for SiC/Si VDMOS.

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3C-SiC on Si: A bio- and hemo-compatible material for advanced nano-bio devices

Abstract: Silicon carbide (SiC) has long been known as a robust semiconductor with superior properties to silicon for electronic applications. The cubic form of SiC, known as 3C-SiC, has been researched for non-electronic applications, such as

Cited by 16 publications

References 15 publications

Demonstration of a Robust All-Silicon-Carbide Intracortical Neural Interface

Demonstration of a Robust All-Silicon-Carbide Intracortical Neural Interface

Fabrication of a Monolithic Implantable Neural Interface from Cubic Silicon Carbide

SiC/Si heterojunction VDMOS breaking silicon limit by breakdown point transfer technology

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