| AVS 64th International Symposium & Exhibition | |
| Plasma Science and Technology Division | Thursday Sessions |
| Session PS+NS+SS+TF-ThM |
| Session: | Atomic Layer Etching I |
| Presenter: | Yoshihide Yamaguchi, Hitachi, Japan |
| Authors: | Y. Yamaguchi, Hitachi, Japan K. Shinoda, Hitachi, Japan Y. Kouzuma, Hitachi High-Technologies Corp., Japan S. Sakai, Hitachi High-Technologies Corp., Japan M. Izawa, Hitachi High-Technologies Corp., Japan |
| Correspondent: | Click to Email |
The demand for thermal atomic level etching (ALEt) of a wide variety of materials including silicon-based materials, metals, and high-k materials is increasing as semiconductor device geometries continue to shrink. To meet the increased demand, remarkable progress into ALEt research has been made in the last few years. One example is the pioneering research on the thermal ALEt of hafnium oxide emerged [1], where hafnium oxide sequentially reacted with HF and a stannous organometallic compound (Sn(acac)2). Thermal ALEt of SiN is another example [2][3], where sequential reactions of a plasma-assisted self-limiting surface modification and a thermal desorption of the self-limiting layer was employed.
In this work, we present our challenge for the thermal ALEt of lanthanum oxide by using surface modification followed by thermal desorption. A key technology of this ALEt is the novel organometallic chemistry for the one-step surface modification of lanthanum oxide. A lanthanum oxide sample exposed to gas of fluorine-containing ketone together with a stabilizer led to the formation of volatile organic species on the sample surface, while a SiO2 sample remained unchanged under the same process condition. The gas-exposed lanthanum oxide sample was then annealed at elevated temperatures under vacuum to remove the volatile species from the surface. After these consecutive processes, the volatile organic species from the lanthanum oxide sample were collected and identified by nuclear magnetic resonance (NMR) spectroscopy and infrared (IR) spectroscopy. These results indicated that the volatile species was an organo-lanthanum complex bearing the fluorine-containing ketone moiety as the ligand. On the basis of these results, a novel selective dry-chemical removal of lanthanum oxide was successfully demonstrated.
Several results on selective dry-chemical removal of lanthanum oxide with respect to TiN, metal oxide, and some other material will also be disclosed.
[1] Y. Lee et al., ECS J. Solid State Sci. Technol. 4. N5013 (2015).
[2] K. Shinoda et al., Appl. Phys. Express 9, 106201 (2016).
[3] K. Shinoda et al., J. Phys. D: Appl. Phys. 50, 194001 (2017).