Conductive Atomic Force Microscopy of Chemically Synthesized Graphene Oxide and Interlayer Conduction

The intrinsic electrical conductivity of graphene is one of the key factors affecting the electrical conductance of its assemblies, such as papers, films, powders, and composites. Here, the local electrical conductivity of the individual graphene flakes was investigated using conductive atomic force microscopy (C-AFM). An isolated graphene flake connected to a pre-fabricated electrode was scanned using an electrically biased tip, which generated a current map over the flake area. The current change as a function of the distance between the tip and the electrode was analyzed analytically to estimate the contact resistance as well as the local conductivity of the flake. This method was applied to characterize graphene materials obtained using two representative large-scale synthesis methods. Monolayer graphene flakes synthesized by chemical vapor deposition on copper exhibited an electrical conductivity of 1.46 ± 0.82 × 106 S/m. Reduced graphene oxide (rGO) flakes obtained by thermal annealing of graphene oxide at 300 and 600 °C exhibited electrical conductivities of 2.3 ± 1.0 and 14.6 ± 5.5 S/m, respectively, showing the effect of thermal reduction on the electrical conductivity of rGO flakes. This study demonstrates an alternative method to characterizing the intrinsic electrical conductivity of graphene-based materials, which affords a clear understanding of the local properties of individual graphene flakes.

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Nanoscale current spreading analysis in solution-processed graphene oxide/silver nanowire transparent electrodes via conductive atomic force microscopy

Journal of Applied Physics ◽

10.1063/1.4949502 ◽

2016 ◽

Vol 119 (19) ◽

pp. 195501 ◽

Cited By ~ 9

Author(s):

Joseph E. Shaw ◽

Ajay Perumal ◽

Donal D. C. Bradley ◽

Paul N. Stavrinou ◽

Thomas D. Anthopoulos

Keyword(s):

Atomic Force Microscopy ◽

Graphene Oxide ◽

Silver Nanowire ◽

Transparent Electrodes ◽

Conductive Atomic Force Microscopy ◽

Solution Processed ◽

Current Spreading ◽

Force Microscopy ◽

Atomic Force

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Fault Isolation of MOL and FEOL Buried Defects Using Conductive Atomic Force Microscopy as a Complement to Passive Voltage Contrast Imaging

ISTFA 2017: Conference Proceedings from the 43rd International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2017p0606 ◽

2017 ◽

Author(s):

Lucile C. Teague Sheridan ◽

Linda Conohan ◽

Chong Khiam Oh

Keyword(s):

Atomic Force Microscopy ◽

Cmos Technology ◽

Fault Isolation ◽

Contrast Imaging ◽

Conductive Atomic Force Microscopy ◽

Isolation Technique ◽

Conductive Afm ◽

Force Microscopy ◽

Atomic Force ◽

Voltage Contrast

Abstract Atomic force microscopy (AFM) methods have provided a wealth of knowledge into the topographic, electrical, mechanical, magnetic, and electrochemical properties of surfaces and materials at the micro- and nanoscale over the last several decades. More specifically, the application of conductive AFM (CAFM) techniques for failure analysis can provide a simultaneous view of the conductivity and topographic properties of the patterned features. As CMOS technology progresses to smaller and smaller devices, the benefits of CAFM techniques have become apparent [1-3]. Herein, we review several cases in which CAFM has been utilized as a fault-isolation technique to detect middle of line (MOL) and front end of line (FEOL) buried defects in 20nm technologies and beyond.

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Fault Localization in Contact Level by Using Conductive Atomic Force Microscopy

ISTFA 2003: Conference Proceedings from the 29th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2003p0413 ◽

2003 ◽

Author(s):

Jon C. Lee ◽

J. H. Chuang

Keyword(s):

Atomic Force Microscopy ◽

Integrated Circuits ◽

Fault Localization ◽

Electrical Characterization ◽

Conductive Atomic Force Microscopy ◽

Force Microscopy ◽

Atomic Force ◽

Optical Electron ◽

Defect Isolation ◽

Voltage Contrast

Abstract As integrated circuits (IC) have become more complicated with device features shrinking into the deep sub-micron range, so the challenge of defect isolation has become more difficult. Many failure analysis (FA) techniques using optical/electron beam and scanning probe microscopy (SPM) have been developed to improve the capability of defect isolation. SPM provides topographic imaging coupled with a variety of material characterization information such as thermal, magnetic, electric, capacitance, resistance and current with nano-meter scale resolution. Conductive atomic force microscopy (C-AFM) has been widely used for electrical characterization of dielectric film and gate oxide integrity (GOI). In this work, C-AFM has been successfully employed to isolate defects in the contact level and to discriminate various contact types. The current mapping of C-AFM has the potential to identify micro-leaky contacts better than voltage contrast (VC) imaging in SEM. It also provides I/V information that is helpful to diagnose the failure mechanism by comparing I/V curves of different contact types. C-AFM is able to localize faulty contacts with pico-amp current range and to characterize failure with nano-meter scale lateral resolution. C-AFM should become an important technique for IC fault localization. FA examples of this technique will be discussed in the article.

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