TY - JOUR

T1 - Plasma Enhanced Atomic Layer Deposition of Tantalum (V) Oxide

AU - Fedorov, Pavel

AU - Назаров, Денис Васильевич

AU - Medvedev, Oleg

AU - Koshtyal, Yury

AU - Rumyantsev, Aleksander

AU - Tolmachev, Vladimir

AU - Popovich, Anatoly

AU - Maximov, Maxim

N1 - Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

PY - 2021/10/1

Y1 - 2021/10/1

N2 - The tantalum oxide thin films are promising materials for various applications: as coatings in optical devices, as dielectric layers for micro and nanoelectronics, and for thin-films solid-state lithium-ion batteries (SSLIBs). This article is dedicated to the Ta-O thin-film system synthesis by the atomic layer deposition (ALD) which allows to deposit high quality films and coatings with excellent uniformity and conformality. Tantalum (V) ethoxide (Ta(OEt)5) and remote oxygen plasma were used as tantalum-containing reagent and oxidizing co-reagent, respectively. The influence of deposition parameters (reactor and evaporator temperature, pulse and purge times) on the growth rate were studied. The thickness of the films were measured by spectroscopic ellipsometry, scanning electron microscopy and X-ray reflectometry. The temperature range of the ALD window was 250–300 C, the growth per cycle was about 0.05 nm/cycle. Different morphology of films deposited on silicon and stainless steel was found. According to the X-ray diffraction data, the as-prepared films were amorphous. But the heat treatment study shows crystallization at 800 C with the formation ofthe polycrystalline Ta2O5 phase with a rhombic structural type (Pmm2). The results of the X-ray reflectometry show the Ta-O films’ density is 7.98 g/cm3, which is close to the density of crystalline Ta2O5 of the rhombic structure (8.18 g/cm3). The obtained thin films have a low roughness and high uniformity. The chemical composition of the surface and bulk of Ta-O coatings was studied by X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy. Surface of the films contain Ta2O5 and some carbon contamination, but the bulk of the films does not contain carbon and any precursor residues. Cyclic voltammetry (CVA) showed that there is no current increase for tantalum (V) oxide in a potential window of 3–4.2 V and has prospects of use as protective coatings for cathode materials of SSLIBs.

AB - The tantalum oxide thin films are promising materials for various applications: as coatings in optical devices, as dielectric layers for micro and nanoelectronics, and for thin-films solid-state lithium-ion batteries (SSLIBs). This article is dedicated to the Ta-O thin-film system synthesis by the atomic layer deposition (ALD) which allows to deposit high quality films and coatings with excellent uniformity and conformality. Tantalum (V) ethoxide (Ta(OEt)5) and remote oxygen plasma were used as tantalum-containing reagent and oxidizing co-reagent, respectively. The influence of deposition parameters (reactor and evaporator temperature, pulse and purge times) on the growth rate were studied. The thickness of the films were measured by spectroscopic ellipsometry, scanning electron microscopy and X-ray reflectometry. The temperature range of the ALD window was 250–300 C, the growth per cycle was about 0.05 nm/cycle. Different morphology of films deposited on silicon and stainless steel was found. According to the X-ray diffraction data, the as-prepared films were amorphous. But the heat treatment study shows crystallization at 800 C with the formation ofthe polycrystalline Ta2O5 phase with a rhombic structural type (Pmm2). The results of the X-ray reflectometry show the Ta-O films’ density is 7.98 g/cm3, which is close to the density of crystalline Ta2O5 of the rhombic structure (8.18 g/cm3). The obtained thin films have a low roughness and high uniformity. The chemical composition of the surface and bulk of Ta-O coatings was studied by X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy. Surface of the films contain Ta2O5 and some carbon contamination, but the bulk of the films does not contain carbon and any precursor residues. Cyclic voltammetry (CVA) showed that there is no current increase for tantalum (V) oxide in a potential window of 3–4.2 V and has prospects of use as protective coatings for cathode materials of SSLIBs.

KW - LIB’s protective coatings

KW - Li-ion batteries

KW - Plasma-enhanced atomic layer deposition

KW - Solid-state batteries

KW - Spectroscopic ellipsometry

KW - Tantalum oxide

KW - Thin films

KW - DIFFUSION BARRIER PROPERTIES

KW - TAN THIN-FILMS

KW - ELECTRICAL-PROPERTIES

KW - li-ion batteries

KW - plasma-enhanced atomic layer deposition

KW - thin films

KW - LIB's protective coatings

KW - spectroscopic ellipsometry

KW - TA2O5

KW - GROWTH

KW - LITHIUM ION BATTERY

KW - solid-state batteries

KW - tantalum oxide

UR - http://www.scopus.com/inward/record.url?scp=85117181066&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/c4a2ae11-6383-358b-a43e-d7302ecd5c6f/

U2 - 10.3390/coatings11101206

DO - 10.3390/coatings11101206

M3 - Article

VL - 11

SP - 1

EP - 15

JO - Coatings

JF - Coatings

SN - 2079-6412

IS - 10

M1 - 1206

ER -