Conformal High-K Dielectric Coating of Suspended Single-Walled Carbon Nanotubes by Atomic Layer Deposition

Nanomaterials

Alexander Tikhonov¹  Aidar Kemelbay¹  TevyeR. Kuykendall²  Shaul Aloni² 

[1] School of Science and Technology, Nazarbayev University, Nur-Sultan 010000, Kazakhstan;The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA;

关键词: carbon nanotube;    atomic layer deposition;    dielectric;    TiO₂;    nucleation layer;   

DOI  :  10.3390/nano9081085

来源: DOAJ

【 摘 要 】

As one of the highest mobility semiconductor materials, carbon nanotubes (CNTs) have been extensively studied for use in field effect transistors (FETs). To fabricate surround-gate FETs— which offer the best switching performance—deposition of conformal, weakly-interacting dielectric layers is necessary. This is challenging due to the chemically inert surface of CNTs and a lack of nucleation sites—especially for defect-free CNTs. As a result, a technique that enables integration of uniform high-k dielectrics, while preserving the CNT’s exceptional properties is required. In this work, we show a method that enables conformal atomic layer deposition (ALD) of high-k dielectrics on defect-free CNTs. By depositing a thin Ti metal film, followed by oxidation to TiO₂ under ambient conditions, a nucleation layer is formed for subsequent ALD deposition of Al₂O₃. The technique is easy to implement and is VLSI-compatible. We show that the ALD coatings are uniform, continuous and conformal, and Raman spectroscopy reveals that the technique does not induce defects in the CNT. The resulting bilayer TiO₂/Al₂O₃ thin-film shows an improved dielectric constant of 21.7 and an equivalent oxide thickness of 2.7 nm. The electrical properties of back-gated and top-gated devices fabricated using this method are presented.

【 授权许可】

Unknown