| AVS 64th International Symposium & Exhibition | |
| Advanced Ion Microscopy Focus Topic | Thursday Sessions |
| Session HI+NS+TR-ThA |
| Session: | Novel Beam Induced Surface Analysis and Nano-Patterning |
| Presenter: | Hiroshi Mizuta, Japan Advanced Institute of Science and Technology (JAIST), Japan |
| Authors: | H. Mizuta, Japan Advanced Institute of Science and Technology (JAIST), Japan M.E. Schmidt, Japan Advanced Institute of Science and Technology (JAIST), Japan T. Kanzaki, Japan Advanced Institute of Science and Technology (JAIST), Japan S. Ogawa, National Institute of Advanced Industrial Science and Technology (AIST), Japan M. Muruganathan, Japan Advanced Institute of Science and Technology (JAIST), Japan |
| Correspondent: | Click to Email |
The bombardment of specimen by accelerated ions causes implantation and surface sputtering. The latter can be employed to create structures with sub-10 nm dimensions. This precision is demonstrated in electrically contacted and suspended graphene layers by a Helium ion microscope (HIM). 5 nm wide monolayer graphene, suspended above a pore and milled by HIM, had been demonstrated [1]. However, the physical properties of such a ribbon cannot be investigated in such a device architecture due to lack of electrical contacts. Recently, we demonstrated a ~6 nm wide suspended GNR and reported on the room temperature electrical characteristics. A wide range of drain current, at which current suppression occurs, has been observed [2]. However, that device was based on exfoliated grapheme, which makes it necessary to individually design the structures, and the yield is typically small.
Here, we report on the large-array processing of 100 nm wide monolayer CVD based suspended graphene structures by HIM. The structures are prepared by electron-beam lithography and thin-film processing. Before HIM milling, the graphene is released by buffered hydrofluoric acid etching and critical point drying. Annealing in H2/Ar atmosphere is used to remove the resist contamination.
We will first discuss results of fabricating suspended GNRs with constriction milled with HIM (30 keV acceleration voltage, 1.1x1018 ion/cm2). The GNRs with sub-10-nm constriction are successfully patterned, and the electrical conduction is measured as function of temperature. We will discuss the milling results and electrical characterization in detail along with their potential impact on the performance of graphene-NEMS-based single-molecular detection [3]. We will then report on the recent progress in preparing arrays of nanopores in graphene by HIM. 9x9 arrays with pitch of ~9 nm are successfully realized with a dose of 6.5x1018 ions/cm2. Arrays of pores spanning a complete suspended ribbon with a pitch of ~18 nm are demonstrated as well, and we will discuss the impact of such periodic structure on the electrical and thermal (phononic) transport for nanoscale heat phonon engineering.
Acknowledgements: T. Iijima is acknowledged for the usage of the HIM at AIST SCR Station. This research was supported through the Grant-in-Aid for Scientific Research KAKENHI 25220904, 16K13650, 16K18090 from JSPS and COI program of the Japan Science Technology Agency.
References [1] D. Pickard and L. Scipioni, “Graphene Nano-Ribbon Patterning in the ORION® PLUS,” Zeiss application note, 2009. [2] M. E. Schmidt et al., 63rd JSAP Spring Meeting (2016) [3] J. Sun et al., Science Advances 2(4), e1501518 (2016)