Why do I observe damage to the contacts in CVD graphene contact fabrication?

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Why Al2O3 and SiO2 are damaged?

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Bubbles and cracks on Al2O3 deposited by ALD on Al(2nm)/graphene/SiO2?Si/ after annealing and wet etching, respectively. Why?

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It seems that Pd gives lowest contact resistivity for graphene devices. What should be deposition rate for e-beam evaporation?

Pd considered good contact material with graphene due to low contact resistivity. Usually, Pd/Au is used. However, deposition rates are not discussed in the papers. What is the deposition rate for Pd?

01 February 2016 1,535 2 View

How can I remove PMMA residue on top of graphene?

Hello, I use PMMA as a resist for E-beam lithography (EBL) to pattern structures on top of graphene. I remove PMMA by using acetone. However, there is always some thin layers of PMMA left on top...

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error in running a model in Abaqus

Excessive rotation of nodes in node set ErrNodeExcessRotation-Step1

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error in modelling model in Abaqus

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MGL tools

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i have some problem with chtMultiRegionSimpleFoam

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What is the production process of CaFe ferroalloys?

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Do you know any MR image dataset?

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What are the new 2D nanomaterials were used for Silver nanoparticles stabilization?

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Zhihong Feng

Reduce Cr thickness down to 5nm and control deposition rate less than 0.5A/s. Otherwise change adhesive layer, such as Ti.

Salamat Burzhuev

Thank you for suggestion! I use 1A/s rate and coat 50nm Cr. Do you think that deposition rate was problem? Or both deposition rate and thickness?

I think both deposition rate and thickness were problem. 50nm Cr was no need. 5nm was enough for adhesion.

Kunpeng Jia

I can not see your picture due to my poor network.

Firstly PMMA residue on cvd grpahene unlikely is the reason for you problem.

And how about your development process? Is PMMA remove totally at metal area?

Finally consider Feng's suggestion. reducing deposition rate and metal layer thickness is beneficial to reduce stress in metal layer.

Thank you for your suggestion and explanation, Kunpeng JIa. I did 1min development in MIBK:IPA 1:3 and observed under microscope. Under optical microscope development seems to be completed.

Satender Kataria

Hi, its seems you have following two reasonsof peeling off

PMMA residue - try to observe by SEM on smaller scale. Micolevel impurity can hamper the adhesion.

Lift off - Try to observe the cross-section of developed resist for contact structures. The profile matters for lift off process.

Thank you for suggestion, Satender. But how I can remove PMMA residue after development?

Thank you, Tillmann. I found this paper intersting

Thanks to Zhihong Feng and Kunpeng Jia !!! I coated 5 nm Cr at slow rate (0.2 A/s) after lift-off and slight sonification I got my pattern.

Previous process doesn't work because of thermal stresses due to fast deposition rate and higher thickness (50 nm). (explained by Kunpeng Jia and Zhihong Feng)

I want to make Cr/Au contacts on top of graphene. What should be the deposition rate of Au?

Serhat yanık

the thickness of pmma and the deposited metal film must be in a ratio of 3:1 otherwise because of the sidewall effect it can not be generated properly. It means ıf your resist has a thickness of ~100nm you can coat max 30 nm thick metal film in order to liftoff