Property transformation of graphene with Al<sub>2</sub>O<sub>3</sub> films deposited directly by atomic layer deposition

Zheng, Lirong; Cheng, Xinbin; Cao, Duo; Wang, Zhongjian; Xia, Changtai; Yu, Yuehui; Shen, Dashen

doi:10.1063/1.4861861

Cited by 30 publications

(31 citation statements)

References 32 publications

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“…In our previous work, we tried to deposit Al 2 O 3 and HfO 2 films directly onto graphene by H 2 O-based ALD. [18][19][20] Al 2 O 3 is known to remain in the amorphous state even upon heating to temperatures as high as 800 1C. However, its relative permittivity (7)(8)(9) is relatively small, which leads to a high EOT.…”

Section: Introductionmentioning

confidence: 99%

Controlled direct growth of Al₂O₃-doped HfO₂ films on graphene by H₂O-based atomic layer deposition

Zheng

Cheng

et al. 2015

Phys. Chem. Chem. Phys.

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Graphene has been drawing worldwide attention since its discovery in 2004. In order to realize graphene-based devices, thin, uniform-coverage and pinhole-free dielectric films with high permittivity on top of graphene are required. Here we report the direct growth of Al2O3-doped HfO2 films onto graphene by H2O-based atom layer deposition (ALD). Al2O3-onto-HfO2 stacks benefited the doping of Al2O3 into HfO2 matrices more than HfO2-onto-Al2O3 stacks did due to the micro-molecular property of Al2O3 and the high chemical activity of trimethylaluminum (TMA). Al2O3 acted as a network modifier, maintained the amorphous structure of the film even to 800 °C, and made the film smooth with a root mean square (RMS) roughness of 0.8 nm, comparable to the surface of pristine graphene. The capacitance and the relative permittivity of Al2O3-onto-HfO2 stacks were up to 1.18 μF cm(-2) and 12, respectively, indicating the high quality of Al2O3-doped HfO2 films on graphene. Moreover, the growth process of Al2O3-doped HfO2 films introduced no detective defects into graphene confirmed by Raman measurements.

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Section: Introductionmentioning

confidence: 99%

Controlled direct growth of Al₂O₃-doped HfO₂ films on graphene by H₂O-based atomic layer deposition

Zheng

Cheng

et al. 2015

Phys. Chem. Chem. Phys.

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“…This is largely due to traces of Al 2 O 3 binding to the graphene defects and grain boundaries. The binding of Al 2 O 3 chemically electron dopes the graphene, improving the graphene electron carrier density [ 49 , 84 ]. As seen in Figure 6 c, the Al 2 O 3 -graphene binding improves the graphene material quality, reducing the number of defects present, and improving performance.…”

Section: Resultsmentioning

confidence: 99%

Application of Molecular Vapour Deposited Al2O3 for Graphene-Based Biosensor Passivation and Improvements in Graphene Device Homogeneity

et al. 2021

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Graphene-based point-of-care (PoC) and chemical sensors can be fabricated using photolithographic processes at wafer-scale. However, these approaches are known to leave polymer residues on the graphene surface, which are difficult to remove completely. In addition, graphene growth and transfer processes can introduce defects into the graphene layer. Both defects and resist contamination can affect the homogeneity of graphene-based PoC sensors, leading to inconsistent device performance and unreliable sensing. Sensor reliability is also affected by the harsh chemical environments used for chemical functionalisation of graphene PoC sensors, which can degrade parts of the sensor device. Therefore, a reliable, wafer-scale method of passivation, which isolates the graphene from the rest of the device, protecting the less robust device features from any aggressive chemicals, must be devised. This work covers the application of molecular vapour deposition technology to create a dielectric passivation film that protects graphene-based biosensing devices from harsh chemicals. We utilise a previously reported “healing effect” of Al2O3 on graphene to reduce photoresist residue from the graphene surface and reduce the prevalence of graphene defects to improve graphene device homogeneity. The improvement in device consistency allows for more reliable, homogeneous graphene devices, that can be fabricated at wafer-scale for sensing and biosensing applications.

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“…237 The Al 2 O 3 atomic layer deposition (ALD) process has been reported to suppress such ambient air caused p-doping in graphene by a self-cleaning effect. 38 To achieve uniform nucleation and growth of the dielectric layer, we first deposit a 1.5 nm thick seed layer of aluminum, 39 which oxidizes spontaneously in air after removing the samples from the vacuum deposition chamber. We then deposit the additional Al 2 O 3 dielectric layer using ALD.…”

Section: Resultsmentioning

confidence: 99%

Tip-based nanofabrication of arbitrary shapes of graphene nanoribbons for device applications

Banerjee

Estrada

et al. 2015

RSC Adv.

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Graphene nanoribbons (GNRs) have promising applications in future nanoelectronics, chemical sensing and electrical interconnects. Although there are quite a few GNR nanofabrication methods reported, a rapid and low-cost fabrication method that is capable of fabricating arbitrary shapes of GNRs with good-quality is still in demand for using GNRs for device applications. In this paper, we present a tip-based nanofabrication method capable of fabricating arbitrary shapes of GNRs. A heated atomic force microscope (AFM) tip deposits polymer nanowires atop a CVD-grown graphene surface. The polymer nanowires serve as an etch mask to define GNRs through one step of oxygen plasma etching similar to a photoresist in conventional photolithography. Various shapes of GNRs with either linear or curvilinear features are demonstrated. The width of the GNR is around 270 nm and is determined by the width of the depositing polymer nanowire, which we estimate can be scaled down 15 nms. We characterize our TBN-fabricated GNRs using Raman spectroscopy and I-V measurements. The measured sheet resistances of our GNRs fall within the range of 1.65 kΩ/□−1 – 2.64 kΩ/□−1, in agreement with previously reported values. Furthermore, we determined the high-field breakdown current density of GNRs to be approximately 2.94×108 A/cm2. This TBN process is seamlessly compatible with existing nanofabrication processes, and is particularly suitable for fabricating GNR based electronic devices including next generation DNA sequencing technologies and beyond silicon field effect transistors.

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Property transformation of graphene with Al₂O₃ films deposited directly by atomic layer deposition

Cited by 30 publications

References 32 publications

Controlled direct growth of Al₂O₃-doped HfO₂ films on graphene by H₂O-based atomic layer deposition

Controlled direct growth of Al₂O₃-doped HfO₂ films on graphene by H₂O-based atomic layer deposition

Application of Molecular Vapour Deposited Al2O3 for Graphene-Based Biosensor Passivation and Improvements in Graphene Device Homogeneity

Tip-based nanofabrication of arbitrary shapes of graphene nanoribbons for device applications

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Property transformation of graphene with Al2O3 films deposited directly by atomic layer deposition

Cited by 30 publications

References 32 publications

Controlled direct growth of Al2O3-doped HfO2 films on graphene by H2O-based atomic layer deposition

Controlled direct growth of Al2O3-doped HfO2 films on graphene by H2O-based atomic layer deposition

Application of Molecular Vapour Deposited Al2O3 for Graphene-Based Biosensor Passivation and Improvements in Graphene Device Homogeneity

Tip-based nanofabrication of arbitrary shapes of graphene nanoribbons for device applications

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Property transformation of graphene with Al₂O₃ films deposited directly by atomic layer deposition

Controlled direct growth of Al₂O₃-doped HfO₂ films on graphene by H₂O-based atomic layer deposition

Controlled direct growth of Al₂O₃-doped HfO₂ films on graphene by H₂O-based atomic layer deposition