Graphene has been considered for a variety of applications including novel nanoelectronic device concepts. However, the deposition of ultra-thin high-k dielectrics on top of graphene has still been challenging due to graphene's lack of dangling bonds. The formation of large islands and leaky films has been observed resulting from a much delayed growth initiation. In order to address this issue, we tested a pre-treatment with NF₃ instead of XeF₂ on CVD graphene as well as epitaxial graphene monolayers prior to the Atomic Layer Deposition (ALD) of Al₂O₃. All experiments were conducted in vacuo; i. e. the pristine graphene samples were exposed to NF₃ in the same reactor immediately before applying 30 (TMA-H₂O) ALD cycles and the samples were transferred between the ALD reactor and a surface analysis unit under high vacuum conditions. The ALD growth initiation was observed by in-situ real-time Spectroscopic Ellipsometry (irtSE) with a sampling rate above 1 Hz. The total amount of Al₂O₃ material deposited by the applied 30 ALD cycles was cross-checked by in-vacuo X-ray Photoelectron Spectroscopy (XPS). The Al₂O₃ morphology was determined by Atomic Force Microscopy (AFM). The presence of graphene and its defect status was examined by in-vacuo XPS and Raman Spectroscopy before and after the coating procedure, respectively.

Date Published: 1 June 2015
PDF: 9 pages
Proc. SPIE 9519, Nanotechnology VII, 951915 (1 June 2015); doi: 10.1117/12.2181242

Published in SPIE Proceedings Vol. 9519:
Nanotechnology VII
Ion M. Tiginyanu, Editor(s)