| AVS 62nd International Symposium & Exhibition | |
| Helium Ion Microscopy Focus Topic | Wednesday Sessions |
| Session HI-WeA |
| Session: | GFIS Based Nanostructuring |
| Presenter: | Marek Schmidt, Japan Advanced Institute of Science and Technology, Japan |
| Authors: | M.E. Schmidt, Japan Advanced Institute of Science and Technology, Japan K. Nagahara, Japan Advanced Institute of Science and Technology O. Takechi, Japan Advanced Institute of Science and Technology M. Akabori, Japan Advanced Institute of Science and Technology A. Yasaka, Hitachi High-Technologies Corporation T. Shimoda, Japan Advanced Institute of Science and Technology H. Mizuta, Japan Advanced Institute of Science and Technology |
| Correspondent: | Click to Email |
We report on the status and application of the gas field ion source (GFIS) focused ion beam (FIB) nanofabrication system [1] located at the Japan Advanced Institute of Science and Technology (JAIST). The atomic emission tip is biased against the extractor, generating high electric field strengths at the tip apex leading to ionization of the source gas. The ions are then accelerated to a typical energy of 25 Kv, focused, and scanned over the device under test (DUT). Such beams can be used to mill the DUT or generate images by simultaneous detection of the secondary electrons by the Everhart-Thornley detector. The GFIS-FIB employs a newly designed emission tip technology to use nitrogen (N2 → N2+) as a high sputter-yield source gas. Other ion species, such as helium and hydrogen, can be generated with the tip technology as well. The latter has been demonstrated to suppress the sub-surface damage formation [2], but is not currently in use at JAIST. Carbon is available for deposition, while iodine, xenon difluoride (XeF2) and H2O can be used for gas assisted milling.
Our current efforts involve carving graphene into sub-10-nm wide ribbons and electrically separating gold electrodes on top of graphene with the goal of realizing graphene tunnel field effect transistors. We also work on fabrication of graphene resonators based on suspended graphene that are narrowed down after the resist-based fabrication and hydrofluoric acid release. The second main area is the preparation of nanoimprint lithography (NIL) masters. Line-and-space pattern with a half pitch of 15 nm were milled into quartz substrates by the ion beam and will be applied to the fabrication of cutting-edge semiconductor devices. Lastly, we use the nitrogen ion beam for quantum point contact fabrication (QPC) in high-in-content InGaAs [3]. The size of the QPCs is ~30 nm × 150 nm, and the QPCs show step-like structures of 2e2/h without magnetic field and of e2/h and 3e2/h with magnetic fields. Additionally, we will show the unique material contrast observed in nitrogen ion excited secondary electron images of graphene-based structures, and talk about low-energy operation, where 15 nm resolution has been achieved with a 5 Kv nitrogen beam. Such low energy beams will be used for defect generation and doping of graphene and other materials.
This work was partially supported by Kakenhi No. 25220904 from JSPS and the Center of Innovation Program from Japan Science and Technology Agency.
[1] F. Aramaki et al., in Proc. SPIE 8441, 84410D, Yokohama, Japan, 2012.
[2] F. Aramaki et al., in Proc. SPIE 7969, 79691C, San Jose, USA, 2011.
[3] M. Akabori et al., Jpn. J. Appl. Phys., 53, 118002, 2014.