Epitaxial graphene on SiC formed by the surface structure control technique

The effects of strong‐acid treatment on an epitaxial graphene film on a SiC substrate are investigated to confirm its stability and compatibility with conventional semiconductor device fabrication processes. An epitaxial graphene film is treated with a strong acid in the form of piranha solution (H2O2 + H2SO4), which is conventionally used in washing processes for the silicon‐based technology. Raman spectroscopy, Hall measurements, and contact angle measurements are carried out before and after piranha treatment. Raman mapping results show no drastic changes before and after piranha treatment. In particular, the D band is not observed after the piranha treatment. From Hall measurements, the electron mobility slightly increases from 920 to 1420 cm2 V−1 s−1 after five piranha treatments. The contact angle is almost constant before (72.8°) and after five piranha treatments (75.2°). These results indicate that the epitaxial graphene film is quite stable under piranha treatment.

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“…Figure b shows the sheet electron density versus electron mobility after each piranha treatment, and the dashed line shows a dependence of

1 / \sqrt{N_{s}}

. The electron mobility values were almost proportional to the inverse of the square root of the sheet electron density

(μ \propto 1 / \sqrt{N_{s}})

, indicating that these changes were caused by doping effects without large scattering centers …”

Section: Resultsmentioning

confidence: 98%

“…Before the piranha treatment, the electron mobility and sheet electron density were 920 cm 2 V −1 s −1 ) and 1.18 × 10 13 cm −2 , respectively, which are typical values of large‐scale epitaxial graphene films on SiC substrates …”

Section: Methodsmentioning

confidence: 88%

High Stability of Epitaxial Graphene on a SiC Substrate

Kujime

Taniguchi

Akiyama

et al. 2019

Physica Status Solidi (b)

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“…Graphene samples were prepared using an infrared rest heat annealing system (Thermo Riko SR-1800). 23) The initial material was a semi-insulating 4H-SiC (0001) substrate of area 100 mm 2 . Six graphene samples were prepared for fabricating three stacked graphene diodes.…”

Section: Fabrication Of Epitaxial Graphene Samplesmentioning

confidence: 99%

Resistive-switching behavior in stacked graphene diode

Ohi

Fukunaga

Murakami

et al. 2023

Jpn. J. Appl. Phys.

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In this study, stacked graphene diodes were fabricated via direct bonding using single-crystal graphene on a SiC substrate. Switching and S-shaped negative resistance were observed in the junction electrical properties measured via the 4-terminal configuration. The high-resistance state switched to the low-resistance state after applying a maximum junction voltage of ~10 V. In the high-bias voltage region, the junction voltage decreased from the maximum junction voltage to a few volts, indicating a negative resistance. In the high-resistance state, junction conductance was nearly constant at 0.13 mS. Electrical conductance in the high-bias region was expressed using an exponential function with an exponent of −1.26. Therefore, the fabricated stacked graphene diode with a simple device structure demonstrated strong nonlinear electrical properties with negative differential conductance.

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“…The graphene samples were epitaxially grown using an infrared rapid thermal annealer (Thermo Riko SR-1800). 21) The initial substrate was a semi-insulating 4H-SiC (0001) substrate (100 mm 2 ). For sample A, the SiC substrate was annealed at 1700 °C in an Ar environment (100 Torr) for 1 s to prepare a buffer layer of one-monolayer carbon.…”

Section: Fabrication Of Epitaxial Graphene Samplesmentioning

confidence: 99%

Blackbody-like infrared radiation in stacked graphene P–N junction diode

Murakami

Sugiyama

Ohno

et al. 2021

Jpn. J. Appl. Phys.

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The electrical and optical properties of a stacked graphene p–n junction were investigated. N-type and p-type graphene films epitaxially grown on a SiC substrate were directly bonded to each other in a face-to-face manner. The current–voltage characteristics of the graphene junction diode exhibited an Ohmic behavior below 20 V. The conductance increased in the bias range above 20 V and had a peak around 65 V. The emission spectrum and temperature of the graphene p–n junction were measured using Fourier-transform far-infrared (FTIR) spectroscopy and infrared bolometer array. An electrically induced blackbody-like radiation with a peak wavelength of 10.2 μm was observed. Although the temperature change estimated using the bolometer results was 66 K at a power of 1.2 W, the peak wavelength of the FTIR spectrum was constant. An electrically induced blackbody-like far-infrared emission diode with a defined peak wavelength was successfully realized using the stacked graphene p–n junctions.

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Epitaxial graphene on SiC formed by the surface structure control technique

Cited by 19 publications

References 34 publications

High Stability of Epitaxial Graphene on a SiC Substrate

High Stability of Epitaxial Graphene on a SiC Substrate

Resistive-switching behavior in stacked graphene diode

Blackbody-like infrared radiation in stacked graphene P–N junction diode

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