Highly Conformal Amorphous W鈥揝i鈥揘 Thin Films by Plasma-Enhanced Atomic Layer Deposition as a Diffusion Barrier for Cu Metallization

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• 作者：Tae Eun Hong ; Jae-Hun Jung ; Seungmin Yeo ; Taehoon Cheon ; So Ik Bae ; Soo-Hyun Kim ; So Jeong Yeo ; Hyo-Suk Kim ; Taek-Mo Chung ; Bo Keun Park ; Chang Gyoun Kim ; Do-Joong Lee
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：January 22, 2015
• 年：2015
• 卷：119
• 期：3
• 页码：1548-1556
• 全文大小：489K
• ISSN：1932-7455

文摘

Ternary and amorphous tungsten silicon nitride (W鈥揝i鈥揘) thin films were grown by atomic layer deposition (ALD) using a sequential supply of a new fluorine-free, silylamide-based W metallorganic precursor, bis(tert-butylimido)bis(bis(trimethylsilylamido))tungsten(VI) [W(N^tBu)₂{N(SiMe₃)₂}₂], and H₂ plasma at a substrate temperature of 300 掳C. Here, W(N^tBu)₂{N(SiMe₃)₂}₂ was prepared through a metathesis reaction of W(N^tBu)₂Cl₂(py)₂ (py = pyridine) with 2 equiv of LiN(SiMe₃)₂ [Li(btsa)]. The newly proposed ALD system exhibited typical ALD characteristics, such as self-limited film growth and linear dependency of the film growth on the number of ALD cycles, and showed a high growth rate of 0.072 nm/cycle on a thermally grown SiO₂ substrate with a nearly zero incubation cycle. Such ideal ALD growth characteristics enabled excellent step coverage of ALD-grown W鈥揝i鈥揘 film, 鈭?00%, onto nanotrenches with a width of 25 nm and an aspect ratio 鈭?.5. Rutherford backscattering spectrometry and X-ray photoelectron spectroscopy analysis confirmed that the incorporated Si and W were mostly bonded to N, as in Si鈥揘 and W鈥揘 chemical bonds. The film kept its amorphous nature until annealing at 800 掳C, and crystallization happened at local areas after annealing at a very high temperature of 900 掳C. An ultrathin (only 鈭? nm thick) ALD-grown W鈥揝i鈥揘 film effectively prevented diffusion of Cu into Si after annealing at a temperature up to 600 掳C.