Atomic layer deposition （ALD） is an emerging technology for thin film deposition. The major advantage of ALD is to conformally deposit uniform dense nano films on structures with a high aspect ratio， and therefore， ALD has a wide range of applications in microelectronics， nanotechnology， and so forth. Compared to conventional micrometer-thick films， nanometer-thick ALD films require more accurate characterization methods. Therefore， this paper discusses the characterization methods particularly for the ALD films. In this paper， common characterization methods for the ALD films are discussed mainly from the aspects of film thickness， composition， crystallinity， and morphology properties， and an outlook is also offered on the future directions of the characterization methods.
[5] KIM H, LEE H-B-R, MAENG W J. Applications of atomic layer deposition to nanofabrication and emerging nanodevices[J]. Thin Solid Films, 2009, 517(8): 2563-2580.
[6] LESKEL? M, RITALA M. Atomic layer deposition (ALD): from precursors to thin film structures[J]. Thin Solid Films, 2002, 409(1): 138-146.
[7] KWON J, DAI M, HALLS M D, et al. In Situ Infrared Characterization during Atomic Layer Deposition of Lanthanum Oxide[J]. The Journal of Physical Chemistry C, 2009, 113(2): 654-660.
[8] MIIKKULAINEN V, LESKEL? M, RITALA M, et al. Crystallinity of inorganic films grown by atomic layer deposition: Overview and general trends[J]. Journal of Applied Physics, 2013, 113(2): 430.
[9] JOHNSON R W, HULTQVIST A, BENT S F. A brief review of atomic layer deposition: from fundamentals to applications[J]. Materials Today, 2014, 17(5): 236-246.
[10] WANG X. Atomic Layer Deposition of Iron, Cobalt, and Nickel Chalcogenides: Progress and Outlook[J]. Chemistry of Materials, 2021, 33(16): 6251-6268.
[11] SHENG Q, WANG L, WANG C, et al. Fabrication of nanofluidic diodes with polymer nanopores modified by atomic layer deposition[J]. Biomicrofluidics, 2014, 8(5): 052111.
[12] MENG X, WANG X, GENG D, et al. Atomic layer deposition for nanomaterial synthesis and functionalization in energy technology[J]. Materials Horizons, 2017, 4(2): 133-154.
[13] WANG J, GUO Z, XIONG W, et al. Synthesis of Thin-Film Metal Pyrites by an Atomic Layer Deposition Approach[J]. Chemistry–A European Journal, 2018, 24(70): 18568-18574.
[14] WANG X, GUO Z. Atomic Layer Deposition for Nanomaterials Synthesis. Handbook of Synthetic Methodologies and Protocols of Nanomaterials: Volume 3: Unconventional Methods for Nanostructure Fabrication [M]. World Scientific, 2020: 257-277.
[15] MUNESHWAR T, MIAO M, BORUJENY E R, et al. Atomic Layer Deposition. Handbook of Thin Film Deposition[M]. William Andrew, 2012.
[16] ZAERA F. The surface chemistry of atomic layer depositions of solid thin films[J]. The Journal of Physical Chemistry Letters, 2012, 3(10): 1301-1309.
[17] CREMERS V, PUURUNEN R L, DENDOOVEN J. Conformality in atomic layer deposition: Current status overview of analysis and modelling[J]. Applied Physics Reviews, 2019, 6(2): 021302.
[19] BARRY S T, TEPLYAKOV A V, ZAERA F. The chemistry of inorganic precursors during the chemical deposition of films on solid surfaces[J]. Accounts of Chemical Research, 2018, 51(3): 800-809.
[20] RICHARTZ M, HSü H-Y J. Analysis of elliptical polarization[J]. Journal of the Optical Society of America, 1949, 39(2): 136-157.
[21] MUNESHWAR T, CADIEN K, et al. Low temperature plasma enhanced atomic layer deposition of conducting zirconium nitride films using tetrakis (dimethylamido) zirconium and forming gas (5% H2+ 95% N2) plasma[J]. Journal of Vacuum Science Technology A: Vacuum, Surfaces, and Films, 2015, 33(3): 031502.
[22] BRISCOE W H, CHEN M, DUNLOP I E, et al. Applying grazing incidence X-ray reflectometry (XRR) to characterising nanofilms on mica[J]. Journal of Colloid and Interface Science, 2007, 306(2): 459-463.
[23] LAMMEL M, GEISHENDORF K, CHOFFEL M A, et al. Fast Fourier transform and multi-Gaussian fitting of XRR data to determine the thickness of ALD grown thin films within the initial growth regime[J]. Applied Physics Letters, 2020, 117(21).
[24] FAN Q, GUO Z, LI Z, et al. Atomic layer deposition of cobalt carbide thin films from cobalt amidinate and hydrogen plasma[J]. ACS Applied Electronic Materials, 2019, 1(3): 444-453.
[25] GUO Z, LI H, CHEN Q, et al. Low-Temperature Atomic Layer Deposition of High Purity, Smooth, Low Resistivity Copper Films by Using Amidinate Precursor and Hydrogen Plasma[J]. Chemistry of Materials, 2015, 27(17): 5988-5996.
[26] LI H, SHAO Y, SU Y, et al. Vapor-phase atomic layer deposition of nickel sulfide and its application for efficient oxygen-evolution electrocatalysis[J]. Chemistry of Materials, 2016, 28(4): 1155-1164.
[27] GUO Z, WANG X. Atomic layer deposition of the metal pyrites FeS2, CoS2, and NiS2 [J]. Angewandte Chemie International Edition, 2018, 57(20): 5898-5902.
[28] SHAO Y, GUO Z, LI H, et al. Atomic Layer Deposition of Iron Sulfide and Its Application as a Catalyst in the Hydrogenation of Azobenzenes[J]. Angewandte Chemie Internation Edition, 2017, 56(12): 3226-3231.
[29] GUO Q, GUO Z, SHI J, et al. Atomic layer deposition of nickel carbide from a nickel amidinate precursor and hydrogen plasma[J]. Acs Applied Materials Interfaces, 2018, 10(9): 8384-8390.
[30] ZHAO R, GUO Z, WANG X. Surface Chemistry during Atomic-Layer Deposition of Nickel Sulfide from Nickel Amidinate and H2S[J]. The Journal of Physical Chemistry C, 2018, 122(37): 21514-21520.
[31] ZHAO R, WANG X. Initial Growth and Agglomeration during Atomic Layer Deposition of Nickel Sulfide[J]. Chemistry of Materials, 2019, 31(2): 445-453.
[32] ZHAO R, ZHANG K, ZHU J, et al. Surface passivation of organometal halide perovskites by atomic layer deposition: an investigation of the mechanism of efficient inverted planar solar cells[J]. Nanoscale Advances, 2021, 3(8): 2305-2315.
[33] GUO Z, ZHAO R, YAN S, et al. Atomic Layer Deposition of FeSe2, CoSe2, and NiSe2 [J]. Chemistry of Materials, 2021, 33(7): 2478-2487.
[34] LIU S, TAN J M, GULEC A, et al. Stabilizing Single-Atom and Small-Domain Platinum via Combining Organometallic Chemisorption and Atomic Layer Deposition[J]. Organometallics, 2017, 36(4): 818-828.
[35] WANG X. (Invited) Atomic Layer Deposition of Cobalt, Nickel, and Iron Sulfides: Synthesis and Applications[J]. ECS Transactions, 2017, 80(3): 77-85.
[36] XIONG W, GUO Q, GUO Z, et al. Atomic layer deposition of nickel carbide for supercapacitors and electrocatalytic hydrogen evolution[J]. Journal of Materials Chemistry A, 2018, 6(10): 4297-4304.
[37] XIONG W, GUO Z, LI H, et al. Rational Bottom-Up Engineering of Electrocatalysts by Atomic Layer Deposition: A Case Study of FexCo1–xSy-Based Catalysts for Electrochemical Hydrogen Evolution[J]. ACS Energy Letters, 2017, 2(12): 2778-2785.
[38] XIONG W, HU K, LI Z, et al. A wearable system based on core-shell structured peptide-Co9S8 supercapacitor and triboelectric nanogenerator[J]. Nano Energy, 2019, 66: 104149.
[39] YAN S, LI H, ZHU J, et al. Atomic layer deposited nickel sulfide for bifunctional oxygen evolution/ reduction electrocatalysis and zinc–air batteries[J]. Nanotechnology, 2021, 32(27): 275402.
[40] LI H, GUO Z, WANG X. Atomic-layer-deposited ultrathin Co9S8 on carbon nanotubes: an efficient bifunctional electrocatalyst for oxygen evolution/reduction reactions and rechargeable Zn–air batteries[J]. Journal of Materials Chemistry A, 2017, 5(40): 21353-21361.
[41] LI H, SHAO Y, SU Y, et al. Vapor-Phase Atomic Layer Deposition of Nickel Sulfide and Its Application for Efficient Oxygen-Evolution Electrocatalysis[J]. Chemistry of Materials, 2016, 28(4): 1155-1164.
[42] LI H, ZHAO R, ZHU J, et al. Organosulfur Precursor for Atomic Layer Deposition of High-Quality Metal Sulfide Films[J]. Chemistry of Materials, 2020, 32(20): 8885-8894.
[43] TANSKANEN J T, H?GGLUND C, BENT S F. Correlating Growth Characteristics in Atomic Layer Deposition with Precursor Molecular Structure: The Case of Zinc Tin Oxide[J]. Chemistry of Materials, 2014, 26(9): 2795-2802.
[44] DAI M, KWON J, LANGEREIS E, et al. In-situ FTIR Study of Atomic Layer Deposition (ALD) of Copper Metal Films[J]. ECS Transactions, 2019, 11(7): 91-101.
[45] MACK J F, VAN STOCKUM P B, YEMANE Y T, et al. Observing the nucleation phase of atomic layer deposition in situ[J]. Chemistry of Materials, 2012, 24(22): 4357-4362.
[46] ZHAO R, GAO Y, GUO Z, et al. Interface Energy Alignment of Atomic-Layer-Deposited VOx on Pentacene: an in Situ Photoelectron Spectroscopy Investigation[J]. ACS Applied Materials Interfaces, 2017, 9(2): 1885-1890.
[47] SMILGIES D M, BUSCH P, PAPADAKIS C M, et al. Characterization of polymer thin films with small‐angle X‐ray scattering under grazing incidence (GISAXS)[J]. Synchrotron Radiation News, 2002 , 15(5):35-42 .
[48] DENDOOVEN J, RAMACHANDRAN R K, SOLANO E, et al. Independent tuning of size and coverage of supported Pt nanoparticles using atomic layer deposition[J]. Nature Communications, 2017, 8(1): 1-12.
[49] TIMM R, HEAD A R, YNGMAN S, et al. Self-cleaning and surface chemical reactions during hafnium dioxide atomic layer deposition on indium arsenide[J]. Nature Communications, 2018, 9(1): 1-9.
[50] TREJO O, DADLANI A L, DE LA PAZ F, et al. Elucidating the evolving atomic structure in atomic layer deposition reactions with in situ XANES and machine learning[J]. Chemistry of Materials, 2019, 31(21): 8937-8947.
