Fabrication of CVD graphene-based devices via laser ablation for wafer-scale characterization

David M A Mackenzie,Patrick R Whelan,Jonas D Buron,Amaia Zurutuza,Amaia Pesquera,Adnan Silajdźić,Dirch H Petersen,Peter Bøggild,Alba Centeno,Bjarke S Jessen

doi:10.1088/2053-1583/2/4/045003

David M A Mackenzie, Patrick R Whelan + Show 8 more

Open Access

https://doi.org/10.1088/2053-1583/2/4/045003

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Abstract

Selective laser ablation of a wafer-scale graphene film is shown to provide flexible, high speed (1 wafer/hour) device fabrication while avoiding the degradation of electrical properties associated with traditional lithographic methods. Picosecond laser pulses with single pulse peak fluences of 140 mJ cm−2 for 1064 nm, 40 mJ cm−2 for 532 nm, and 30 mJ cm−2 for 355 nm are sufficient to ablate the graphene film, while the ablation onset for Si/SiO2 (thicknesses 500 μm/302 nm) did not occur until 240 mJ cm−2, 150 mJ cm−2, and 135 mJ cm−2, respectively, allowing all wavelengths to be used for graphene ablation without detectable substrate damage. Optical microscopy and Raman Spectroscopy were used to assess the ablation of graphene, while stylus profilometery indicated that the SiO2 substrate was undamaged. CVD graphene devices were electrically characterized and showed comparable field-effect mobility, doping level, on–off ratio, and conductance minimum before and after laser ablation fabrication.

Highlights

While the introduction of copper-based catalytic chemical vapor deposition of graphene (Li et al 2010) has led to the scale-up to m2-sized single layer graphene, the available methods for measuring the electrical properties of graphene are generally slow, inefficient and inadequate for large-area, large-volume characterization
Picosecond laser pulses with single pulse peak fluences of 140 mJ cm−2 for 1064 nm, 40 mJ cm−2 for 532 nm, and 30 mJ cm−2 for 355 nm are sufficient to ablate the graphene film, while the ablation onset for Si/SiO2 did not occur until 240 mJ cm−2, 150 mJ cm−2, and 135 mJ cm−2, respectively, allowing all wavelengths to be used for graphene ablation without detectable substrate damage
We demonstrate that picosecond laser ablation is a viable fabrication route for high-speed laser fabrication of wafer-scale graphene devices

Summary

Introduction

While the introduction of copper-based catalytic chemical vapor deposition of graphene (Li et al 2010) has led to the scale-up to m2-sized single layer graphene, the available methods for measuring the electrical properties of graphene are generally slow, inefficient and inadequate for large-area, large-volume characterization. The lack of large-area quality control can become an increasingly serious problem as the demand for throughput and consistency increases. Standard lithographic methods are time-consuming, but unavoidably require graphene to come into contact with polymers/solvents/ liquids that may permanently and adversely alter the electrical properties of graphene (Schedin et al 2007, Goossens et al 2012, Gammelgaard et al 2014). Such unintentional changes can be difficult to distinguish from sample-to-sample variations due to CVD growth and transfer parameters. A method which avoids traditional lithography would be an important improvement towards better large-scale characterization and device fabrication

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