Final Report Summary - NANOFAB4CNT (Novel bottom-up nanofabrication techniques for future carbon-nanoelectronics)
The aim of this research program was to make a key contribution to the development of new reliable nanofabrication techniques for controlled carbon nanotube (CNT growth), placement and CNT-FET fabrication using a 'bottom-up' approach to overcome the current manufacturing challenges. In this ‘bottom-up’ approach small individual components, such as carefully placed CNT catalyst particles and nanoscale contacts, were to be used to build up more complex assemblies, such as CNT FETs, without the need for photo-lithography.
In the last four years single-walled carbon nanotube growth facilities have been built up at the host institution based on a chemical vapor deposition process and solution processed catalyst particles. The growth related efforst has been focused on obtaining aligned CNT growth using oblique ion beam treatments. The research has shown that oblique ion beam treatments are able to align CNTs during growth, but further research is needed to get insight into 100% CNT alignment, without deviation of part of the CNTs.
The fabrication of contacts to carbon nanotubes using a novel resist-free direct-write technique based on electron beam induced deposition followed by selective atomic layer deposition (direct-write ALD) has also been demonstrated. This combined approach gives high-quality material (virtually 100% pure Pt, resistivity of 12 µΩcm), and a high lateral resolution (~10 nm). Furthermore, the fabrication of the first carbon nanotube field effect transistors (CNTFETs) using this technique has been reported. Electrical characterization of the CNTFETs revealed that the contact quality of Pt contacts deposited by direct-write ALD are of similar quality as the commonly used Pd contacts patterned by lithography.
The same technique was applied to fabricate contacts to graphene. Large-area CVD graphene sheets were patterned into device channels by direct exposure to a focused ion beam. Platinum contacts were then deposited by direct-write atomic layer deposition, which is a unique combination between electron beam induced deposition (EBID) and bottom-up area-selective atomic layer deposition (ALD). These devices are the first reported graphene devices with contacts deposited by ALD.
Since obtaining the Marie Curie Career Integration Grant the fellow has built up her own research group, which currently consists of 7 PhD students and 3 Postdocs. She obtained a tenured associate professorship at Eindhoven University of technology on 01-01-2015. 5.75MEuro in research funding was obtained by the fellow in the reported period.
In the last four years single-walled carbon nanotube growth facilities have been built up at the host institution based on a chemical vapor deposition process and solution processed catalyst particles. The growth related efforst has been focused on obtaining aligned CNT growth using oblique ion beam treatments. The research has shown that oblique ion beam treatments are able to align CNTs during growth, but further research is needed to get insight into 100% CNT alignment, without deviation of part of the CNTs.
The fabrication of contacts to carbon nanotubes using a novel resist-free direct-write technique based on electron beam induced deposition followed by selective atomic layer deposition (direct-write ALD) has also been demonstrated. This combined approach gives high-quality material (virtually 100% pure Pt, resistivity of 12 µΩcm), and a high lateral resolution (~10 nm). Furthermore, the fabrication of the first carbon nanotube field effect transistors (CNTFETs) using this technique has been reported. Electrical characterization of the CNTFETs revealed that the contact quality of Pt contacts deposited by direct-write ALD are of similar quality as the commonly used Pd contacts patterned by lithography.
The same technique was applied to fabricate contacts to graphene. Large-area CVD graphene sheets were patterned into device channels by direct exposure to a focused ion beam. Platinum contacts were then deposited by direct-write atomic layer deposition, which is a unique combination between electron beam induced deposition (EBID) and bottom-up area-selective atomic layer deposition (ALD). These devices are the first reported graphene devices with contacts deposited by ALD.
Since obtaining the Marie Curie Career Integration Grant the fellow has built up her own research group, which currently consists of 7 PhD students and 3 Postdocs. She obtained a tenured associate professorship at Eindhoven University of technology on 01-01-2015. 5.75MEuro in research funding was obtained by the fellow in the reported period.