Atomic layer deposition(ALD)has become an indispensable thin-film technology in the contemporary microelectronics industry.The unique self-limited layer-by-layer growth feature of ALD has outstood this technology to d...Atomic layer deposition(ALD)has become an indispensable thin-film technology in the contemporary microelectronics industry.The unique self-limited layer-by-layer growth feature of ALD has outstood this technology to deposit highly uniform conformal pinhole-free thin films with angstrom-level thickness control,particularly on 3D topologies.Over the years,the ALD technology has enabled not only the successful downscaling of the microelectronic devices but also numerous novel 3D device structures.As ALD is essentially a variant of chemical vapor deposition,a comprehensive understanding of the involved chemistry is of crucial importance to further develop and utilize this technology.To this end,we,in this review,focus on the surface chemistry and precursor chemistry aspects of ALD.We first review the surface chemistry of the gas–solid ALD reactions and elaborately discuss the associated mechanisms for the film growth;then,we review the ALD precursor chemistry by comparatively discussing the precursors that have been commonly used in the ALD processes;and finally,we selectively present a few newly-emerged applications of ALD in microelectronics,followed by our perspective on the future of the ALD technology.展开更多
A strong influence of nitrogen gas on the content of surface hydroxyl groups of TiO2 films by atomic layer deposition（ALD） was investigated by X-ray photoelectron spectroscopy（XPS）, contact angle measuring system,...A strong influence of nitrogen gas on the content of surface hydroxyl groups of TiO2 films by atomic layer deposition（ALD） was investigated by X-ray photoelectron spectroscopy（XPS）, contact angle measuring system, and UV–Vis spectrophotometer. XPS spectra of O 1s indicate that the content of surface hydroxyl groups is varied when using N2 as carrier gas. The results of water contact angles and optical reflection spectra show that the content variation of surface hydroxyl groups influences the wetting properties and optical reflectivity of TiO2 films. A surface reaction model is suggested to explain the ALD reaction process using N2 as carrier gas.展开更多
Atomic layer deposition(ALD) as a flexible surface-controlled fabrication technique has attracted widespread interest in numerous nanotechnology applications, which can obtain ultrathin or two-dimensional molybdenum d...Atomic layer deposition(ALD) as a flexible surface-controlled fabrication technique has attracted widespread interest in numerous nanotechnology applications, which can obtain ultrathin or two-dimensional molybdenum disulfide(2D MoS2) films.The ALD technique possesses the characteristics of precise thickness control, excellent uniformity, and conformality, relying on the self-limiting surface reaction. In this mini-review, the knowledge about the fabrication mechanisms and applications of ALD prepared MoS2 films is reviewed. The surface reaction pathway about ALD synthesis MoS2 is elaborated, and the corresponding factors causing saturation adsorption are discussed. Two possible growth mechanisms of ALD-MoS2 film based on the building blocks and MoS2 islands are compared. For both, the deposition process of MoS2 can be divided into two stages, heterogeneous deposition stage and homogeneous deposition stage. The mismatch between the as-deposited MoS2 in the heterodeposition and the lattice structure of the substrate surface is a key factor leading to the poor crystallinity of as-deposited MoS2. In addition, the extensions of ALD MoS2 technique to improve the as-deposited film quality are discussed. Finally, the applications of ALD deposited MoS2 film are summarized, and future perspectives are outlined.展开更多
We present a multi-level growth model that yields some of the key features of perovskite oxide film growth as observed in the reflection high energy electron diffraction （RHEED） and ellipsometry studies. The model d...We present a multi-level growth model that yields some of the key features of perovskite oxide film growth as observed in the reflection high energy electron diffraction （RHEED） and ellipsometry studies. The model describes the effect of deposition, temperature, intra-layer transport, interlayer transport and Ostwald ripening on the morphology of a growth surface in terms of the distribution of terraces and step edges during and after deposition. The numerical results of the model coincide well with the experimental observation.展开更多
基金supported by NSFC(22175005)Guangdong Basic and Applied Basic Research Foundation(2020B1515120039)+1 种基金Shenzhen Fundamental Research Program(JCYJ20200109110628172,GXWD20201231165807007-20200802205241003)Guangdong Technology Center for Oxide Semiconductor Devices and ICs。
文摘Atomic layer deposition(ALD)has become an indispensable thin-film technology in the contemporary microelectronics industry.The unique self-limited layer-by-layer growth feature of ALD has outstood this technology to deposit highly uniform conformal pinhole-free thin films with angstrom-level thickness control,particularly on 3D topologies.Over the years,the ALD technology has enabled not only the successful downscaling of the microelectronic devices but also numerous novel 3D device structures.As ALD is essentially a variant of chemical vapor deposition,a comprehensive understanding of the involved chemistry is of crucial importance to further develop and utilize this technology.To this end,we,in this review,focus on the surface chemistry and precursor chemistry aspects of ALD.We first review the surface chemistry of the gas–solid ALD reactions and elaborately discuss the associated mechanisms for the film growth;then,we review the ALD precursor chemistry by comparatively discussing the precursors that have been commonly used in the ALD processes;and finally,we selectively present a few newly-emerged applications of ALD in microelectronics,followed by our perspective on the future of the ALD technology.
基金financially supported by the National Science and Technology Major Project (No. 2009ZX02037-003)the China Postdoctoral Science Foundation (No. 2011M500996)
文摘A strong influence of nitrogen gas on the content of surface hydroxyl groups of TiO2 films by atomic layer deposition（ALD） was investigated by X-ray photoelectron spectroscopy（XPS）, contact angle measuring system, and UV–Vis spectrophotometer. XPS spectra of O 1s indicate that the content of surface hydroxyl groups is varied when using N2 as carrier gas. The results of water contact angles and optical reflection spectra show that the content variation of surface hydroxyl groups influences the wetting properties and optical reflectivity of TiO2 films. A surface reaction model is suggested to explain the ALD reaction process using N2 as carrier gas.
基金supported by the National Natural Science Foundation of China(Grant No.51822501)the Natural Science Foundation of Jiangsu Province(Grant Nos.BK20170023,BK20181274)+8 种基金the Fundamental Research Funds for the Central Universities(Grant Nos.3202006301,3202006403)the Qing Lan Project of Jiangsu Provincethe International Foundation for Science,Stockholm,Swedenthe Organization for the Prohibition of Chemical Weapons,The Hague,Netherlands,through a grant to Lei Liu(F/4736-2)the grants from Top 6 High-Level Talents Program of Jiangsu Province(Grant No.2017-GDZB-006,Class A)the Tribology Science Fund of State Key Laboratory of Tribology(Grant No.SKLTKF15A11)Open Research Fund of State Key Laboratory of High Performance Complex Manufacturing,Central South University(Grant No.Kfkt2016-11)Open Research Fund of State Key Laboratory of Fire Science(Grant No.HZ2017-KF05)Open Research Fund of State Key Laboratory of Solid Lubrication(Grant No.LSL-1607)。
文摘Atomic layer deposition(ALD) as a flexible surface-controlled fabrication technique has attracted widespread interest in numerous nanotechnology applications, which can obtain ultrathin or two-dimensional molybdenum disulfide(2D MoS2) films.The ALD technique possesses the characteristics of precise thickness control, excellent uniformity, and conformality, relying on the self-limiting surface reaction. In this mini-review, the knowledge about the fabrication mechanisms and applications of ALD prepared MoS2 films is reviewed. The surface reaction pathway about ALD synthesis MoS2 is elaborated, and the corresponding factors causing saturation adsorption are discussed. Two possible growth mechanisms of ALD-MoS2 film based on the building blocks and MoS2 islands are compared. For both, the deposition process of MoS2 can be divided into two stages, heterogeneous deposition stage and homogeneous deposition stage. The mismatch between the as-deposited MoS2 in the heterodeposition and the lattice structure of the substrate surface is a key factor leading to the poor crystallinity of as-deposited MoS2. In addition, the extensions of ALD MoS2 technique to improve the as-deposited film quality are discussed. Finally, the applications of ALD deposited MoS2 film are summarized, and future perspectives are outlined.
文摘We present a multi-level growth model that yields some of the key features of perovskite oxide film growth as observed in the reflection high energy electron diffraction （RHEED） and ellipsometry studies. The model describes the effect of deposition, temperature, intra-layer transport, interlayer transport and Ostwald ripening on the morphology of a growth surface in terms of the distribution of terraces and step edges during and after deposition. The numerical results of the model coincide well with the experimental observation.
