Self‐Aligned Sub‐10‐nm Nanogap Electrode Array for Large‐Scale Integration

Abstract

A novel approach to creating a gap on the nanometer scale between two adjacent electrodes of the same or different metals is described. The gap size can be well controlled through sidewall coverage in a self-aligned manner and it can be tuned from 60 nm down to 5 nm with high reproducibility. This technique is fully compatible with traditional microfabrication technology and it is easily implemented to fabricate a nanogap electrode array for integration purposes. An array of short-channel single-walled carbon nanotube field-effect transistors is demonstrated.

Sub-15-nm patterning of asymmetric metal electrodes and devices by adhesion lithography

“…The patterning resolution that can be achieved using a-lith compares favourably with the very few reports of aligned asymmetric nanogaps in the literature45, which have utilized e-beam lithography to achieve the requisite registration of the two metals. Using a combination of optical lift-off lithography, e-beam lithography, plasma-enhanced vapour deposition and chemical etching, Gao et al 4 reported an 11-step route to asymmetric electrodes capable of yielding well aligned nanogaps of Ti and Au down to 5 nm.…”

“…Using a combination of optical lift-off lithography, e-beam lithography, plasma-enhanced vapour deposition and chemical etching, Gao et al 4 reported an 11-step route to asymmetric electrodes capable of yielding well aligned nanogaps of Ti and Au down to 5 nm. Guillorn et al 5 meanwhile reported a sophisticated procedure, utilizing high-resolution e-beam lithography, two stages of reactive ion etching, thermal and electron gun physical vapour deposition of the metals and lift-off pattern transfer to achieve asymmetric electrode pairs of Au and Pt, Ti, Pd or Al with interelectrode spacings of 6 nm.…”

“…Existing fabrication routes entail the use of electron-beam lithography3456, mechanical break junctions78, electrochemical deposition91011, oblique-angle shadow-evaporation12, scanning probe lithography13 or on-wire lithography14 to achieve intimate registration of the two electrodes. Such methods, however, variously suffer from low throughput, poor scalability to larger substrate sizes, complex multi-step processing protocols, and/or high equipment costs115.…”

Fabrication of sub-1 nm gap electrodes using metal-mask patterning and conductivity measurements of molecules in nanoscale spaces

“…Various methods have been applied to form nanogaps with specic widths, like electron-beam lithography, 7,8 electroplating, 9 molecular lithography, [9][10][11][12] shadow evaporation, 13 and electromigration, 14 among others. [15][16][17][18][19][20] In a previous study, 21 we successfully developed a method for nanogap fabrication in which a voltage is applied during metal deposition, inducing the electromigration of the metals. We applied this method to form self-aligned nanogaps as small as 1 nm in width and found that the gap width could be controlled by changing the magnitude of the applied voltage.…”

Fabrication of a Carbon‐Nanotube‐Based Field‐Effect Transistor by Microcontact Printing

“…The patterning of CNTs is particularly relevant for the preparation of nanoscale devices and sensors based on the outstanding electronic properties of CNTs 2. Patterned arrays of CNTs are usually obtained by first patterning a catalyst onto a suitable substrate, for example by evaporation through a mask or alternatively by soft lithographic methods such as μCP.…”