原子层沉积技术及其在铁电薄膜制备中的应用

讲述原子层沉积技术原理与特点的同时,进一步论述了它在沉积机理和实验真空度这两方面与传统薄膜沉积工艺的异同;综述了此技术在铁电薄膜制备研究方面的最新进展,前驱体的制备与选择、薄膜缺陷的控制以及表面化学反应动力学依然是当前原子层制备铁电薄膜研究的重点;最后展望了原子层沉积技术制备铁电薄膜的发展方向.     

等离子体增强原子层沉积技术制备过渡金属薄膜的研究进展

原子级的处理对应用于计算和数据存储的最先进的电子设备,以及与物联网、人工智能和量子计算相关的新兴技术正变得越来越重要。等离子体增强原子层沉积(PEALD)是一种原子级表面沉积技术,由于其较高的反应活性以及较低的沉积温度日益受到研究者的关注。本文介绍了PEALD技术的基本原理以及相对于其他薄膜沉积技术的优势,之后从前驱体和基底材料的影响等方面介绍了利用PEALD制备Ti、Co、Ni、Cu、Ru、Pd、Ag、Ta、Ir和Pt等过渡金属薄膜以及它们在微电子领域的应用现状,最后进行了总结和展望。     

原子层沉积技术及其在铁电薄膜制备中的应用

讲述原子层沉积技术原理与特点的同时，进一步论述了它在沉积机理和实验真空度这两方面与传统薄膜沉积工艺的异同；综述了此技术在铁电薄膜制备研究方面的最新进展，前驱体的制备与选择、薄膜缺陷的控制以及表面化学反应动力学依然是当前原子层制备铁电薄膜研究的重点；最后展望了原子层沉积技术制备铁电薄膜的发展方向。     

原子层沉积技术的研究进展

介绍了原子层沉积技术的基本原理,与其他的薄膜制备方法进行了优缺点比较;同时论述了它在前驱体的选择以及实验装置方面的研究进展;指出前驱体的制备和选择、低沉积速率的改进是当前原子层沉积技术研究的重点;最后展望了原子层沉积技术的发展前景。     

原子层沉积技术及应用发展概况

首先回顾了原子层沉积(ALD)发展历史,介绍了ALD的基本工艺和ALD薄膜具有的优良特性,并与传统的薄膜制备工艺进行了对比研究.重点阐述了ALD在微电子技术、微电子机械系统以及光学工程中的几个应用研究现状.分析了ALD目前存在的问题,并对ALD未来的发展进行了展望.     

原子层沉积技术在新型太阳能电池中的应用

原子层沉积技术(ALD)是一项正处于发展之中、在许多领域具有巨大应用前景的新型材料制备技术,该技术在纳米结构和纳米复合结构的制备方面显示出独特的优势,在新型薄膜太阳能电池领域呈现出巨大的发展潜力和前景。首先概述了ALD技术的工作原理,简要介绍了近几年ALD技术在硅基太阳能电池和铜铟镓硒薄膜电池(CIGS)中的应用,然后重点综述了原子层沉积纳米功能薄膜在染料敏化太阳能电池(DSSCs)和有机-无机杂化钙钛矿太阳能电池(PSCs)为代表的新型薄膜太阳能电池中的应用。最后,总结了原子层沉积功能薄膜的特点和优势,展望了ALD在新能源材料与器件领域的应用前景和发展趋势。     

原子层沉积系统设计的研究

本文介绍作者自行设计的原子层沉积(ALD)实验系统和所沉积薄膜的检测结果。为了研究ALD技术,作者设计了一套试验性的ALD沉积系统。该系统主要由反应腔、前驱体容器、真空泵、控制系统等部件构成。两个前驱体容器带有加热装置,支持气体或液体前驱体。前驱体、反应腔的温度,沉积过程中气体的交替,以及各种参数都可以设定,并由控制系统自动控制。在系统测试中,使用Al2(CH3)3和H2O作为前驱体,在含有Si-H键的Si基片上沉积Al2O3高k介质薄膜。使用电子探针分析仪分析薄膜成分后,证实了所沉积的薄膜是Al2O3。使用XPS分析薄膜表面时只检测到Al,O元素,没有检测到Si元素,说明Al2O3薄膜是连续的,完整地覆盖了Si表面。使用X射线光电子谱检测元素面分布的结果显示,Al,O在Si上的分布具有较好均一性,表明Al2O3薄膜的均匀性良好。使用电子束照射已沉积Al2O3的Si基片时,发现有大量电子累积在薄膜表面,说明所沉积的Al2O3具有良好的介电性。     

原子层沉积技术及其在光学薄膜中的应用

回顾了原子层沉积(ALD)技术的发展背景,通过分析ALD的基本工艺,并与传统薄膜制备工艺进行了对比研究.介绍了它在膜层的均匀性、保形性以及膜厚控制能力等方面的优势.着重列举ALD在减反膜、紫外截止膜、折射率可调的薄膜、抗激光损伤薄膜及复杂结构光子晶体等方面的应用.同时指出了目前ALD工艺在光学薄膜应用中存在的主要问题,并对ALD未来的发展进行了展望.     

聚乙烯醇改性对原子层沉积氧化铝复合隔膜的影响

原子层沉积技术(ALD)是一种具有表面自限性反应的薄膜生长技术,可以精准控制薄膜的生长。本文研究了ALD技术包覆聚烯烃隔膜,制作纳米氧化铝聚烯烃复合隔膜。聚烯烃膜表面无ALD氧化铝反应基团,造成ALD氧化铝生长成核慢,前期反应效率低,最终生长的氧化铝多形成团簇而非完整覆盖的薄膜。为了增强ALD氧化铝包覆聚乙烯膜(PE)的全覆盖薄膜生长,将PE膜进行了聚乙烯醇(PVA)表面改性处理,然后进行ALD Al₂O₃生长。通过扫描电镜、红外光谱、电感耦合发射光谱仪等技术手段系统分析了PVA表面改性对ALD Al₂O₃包覆PE膜性能指标的影响。结果表明,PVA改性可以简单有效地在PE膜上增加羟基(-OH)作为ALD反应位点。处理后的PE膜进行ALD Al₂O₃生长,前驱体进入反应腔室后更易与表面羟基进行反应,提高表面生长效率,纤维上均匀包覆氧化铝,无岛状生长的Al₂O₃团簇。同时PVA改性可以增强复合膜的耐热收缩性能,减少厚度增加,减轻机械结构的损坏。     

钯金属薄膜制备方法的研究现状与进展

近年来,钯金属薄膜由于具有电阻率低和催化活性高等优异性能引起人们的广泛关注,钯及其合金薄膜在集成电路互连应用、氢传感、储氢和催化方面获得了越来越多科研工作者的兴趣。目前已有诸多制备钯金属薄膜的研究,本文重点介绍了利用物理气相沉积技术、化学气相沉积技术、原子层沉积技术以及等离子体辅助原子层沉积技术制备钯薄膜的研究现状,讨论了各种制备方法的优缺点,对所使用的前驱体作了总结,并展望了钯薄膜制备技术未来发展趋势。     

Effects of the substrate temperature on the Cu seed layer formed using atomic layer deposition

Cu has replaced Al as the main interconnection material in ultra-large integrated circuits, reducing resistance capacitance delay and yielding higher electro-migration reliability. As feature size decreases, however, it has become more difficult to produce reliable Cu wiring. We studied a Cu seed layer deposited using plasma enhanced atomic layer deposition (PEALD). The electrical properties of the PEALD Cu thin film with sub-10 nm thickness were determined by the continuities and morphologies of the films. At a deposition temperature of 150 °C, the resistivity of Cu thin films was 5.2 μΩ-cm and the impurity content was below 5 atomic %. Based on these results, Cu seed layers were deposited on 32-nm Ta/SiO2 trench substrates, and electrochemical plating was performed under conventional conditions. A continuous seed layer was deposited using PEALD, resulting in a perfectly filling of the 32-nm sized trench.     

From Precursor Chemistry to Gas Sensors: Plasma‐Enhanced Atomic Layer Deposition Process Engineering for Zinc Oxide Layers from a Nonpyrophoric Zinc Precursor for Gas Barrier and Sensor Applications

The identification of bis‐3‐(N,N‐dimethylamino)propyl zinc ([Zn(DMP)₂], BDMPZ) as a safe and potential alternative to the highly pyrophoric diethyl zinc (DEZ) as atomic layer deposition (ALD) precursor for ZnO thin films is reported. Owing to the intramolecular stabilization, BDMPZ is a thermally stable, volatile, nonpyrophoric solid compound, however, it possesses a high reactivity due to the presence of Zn‐C and Zn‐N bonds in this complex. Employing this precursor, a new oxygen plasma enhanced (PE)ALD process in the deposition temperature range of 60 and 160 °C is developed. The resulting ZnO thin films are uniform, smooth, stoichiometric, and highly transparent. The deposition on polyethylene terephthalate (PET) at 60 °C results in dense and compact ZnO layers for a thickness as low as 7.5 nm with encouraging oxygen transmission rates (OTR) compared to the bare PET substrates. As a representative application of the ZnO layers, the gas sensing properties are investigated. A high response toward NO₂ is observed without cross‐sensitivities against NH₃ and CO. Thus, the new PEALD process employing BDMPZ has the potential to be a safe substitute to the commonly used DEZ processes.     

Growth behavior of iridium on Si substrates prepared by plasma enhanced atomic layer deposition

Growth behavior of iridium (Ir) thin film on Si substrates prepared by plasma enhanced atomic layer deposition (PEALD) was systematically studied. Ir(EtCp)(COD) and oxygen was employed as a precursor and reactant, respectively. To obtain optimal conditions for depositing nanometer scale Ir thin film, deposition temperature, cycle dependence and precursor feeding time dependence were studied. Uniform 12 nm thick Ir layer with sharp interface was grown at the temperature range of 330-360 degrees C at the fixed deposition cycles of 300. The grown Ir film showed linear properties as a function of deposition cycles which is a typical self-limiting characteristic of ALD. The XRD patterns revealed that IrOx was not formed due to relatively low partial pressure of oxygen. The optimal conditions obtained for 12 nm thick Ir thin film were 330 degrees C of deposition temperature, 300 deposition cycles, and 10 sec of precursor feeding time.     

Atomic Layer Deposition on Dispersed Materials in Liquid Phase by Stoichiometrically Limited Injections

Atomic layer deposition (ALD) is a well‐established vapor‐phase technique for depositing thin films with high conformality and atomically precise control over thickness. Its industrial development has been largely confined to wafers and low‐surface‐area materials because deposition on high‐surface‐area materials and powders remains extremely challenging. Challenges with such materials include long deposition times, extensive purging cycles, and requirements for large excesses of precursors and expensive low‐pressure equipment. Here, a simple solution‐phase deposition process based on subsequent injections of stoichiometric quantities of precursor is performed using common laboratory synthesis equipment. Precisely measured precursor stoichiometries avoid any unwanted reactions in solution and ensure layer‐by‐layer growth with the same precision as gas‐phase ALD, without any excess precursor or purging required. Identical coating qualities are achieved when comparing this technique to Al₂O₃ deposition by fluidized‐bed reactor ALD (FBR‐ALD). The process is easily scaled up to coat >150 g of material using the same inexpensive laboratory glassware without any loss in coating quality. This technique is extended to sulfides and phosphates and can achieve coatings that are not possible using classic gas‐phase ALD, including the deposition of phosphates with inexpensive but nonvolatile phosphoric acid.     

柔性高阻隔薄膜材料的研究现状

目的为柔性高阻隔薄膜的应用提供理论指导。方法综述柔性高阻隔膜的应用现状及存在问题,总结热蒸发、化学气相沉积、原子层沉积等制备柔性高阻隔薄膜的方法、原理、特点及应用,展望高阻隔膜包装材料的发展前景。结果高阻隔薄膜制备工艺趋向于单次制备,采用等离子体辅助原子层沉积技术是制备超高阻隔薄膜的首选,原子层沉积(ALD)和分子层沉积(MLD)结合也是获得超高阻隔薄膜的未来发展方向。结论快速、高效地制备柔性高阻隔薄膜是包装工业的发展趋势。     

Atomic Layer Deposition of Nanostructured Materials for Energy and Environmental Applications

Atomic layer deposition (ALD) is a thin film technology that in the past two decades rapidly developed from a niche technology to an established method. It proved to be a key technology for the surface modification and the fabrication of complex nanostructured materials. In this Progress Report, after a short introduction to ALD and its chemistry, the versatility of the technique for the fabrication of novel functional materials will be discussed. Selected examples, focused on its use for the engineering of nanostructures targeting applications in energy conversion and storage, and on environmental issues, will be discussed. Finally, the challenges that ALD is now facing in terms of materials fabrication and processing will be also tackled.     

A Chemical Route to Monolithic Integration of Crystalline Oxides on Semiconductors

This work demonstrates the growth of crystalline SrTiO₃ (STO) directly on germanium via a chemical method. After thermal deoxidation, the Ge substrate is transferred in vacuo to the deposition chamber where a thin film of STO (2 nm) is deposited by atomic layer deposition (ALD) at 225 °C. Following post‐deposition annealing at 650 °C for 5 min, the STO film becomes crystalline with epitaxial registry to the underlying Ge (001) substrate. Thicker STO films (up to 15 nm) are then grown on the crystalline STO seed layer. The crystalline structure and orientation are confirmed via reflection high‐energy electron diffraction, X‐ray diffraction, and transmission electron microscopy. Electrical measurements of a 15‐nm thick epitaxial STO film on Ge show a large dielectric constant (k ≈ 90), but relatively high leakage current of ≈10 A/cm² for an applied field of 0.7 MV/cm. To suppress the leakage current, an aluminum precursor is cycled during ALD growth to grow crystalline Al‐doped STO (SrTi_1‐x­Al_xO_3‐δ) films. With sufficient Al doping (≈13%), the leakage current decreases by two orders of magnitude for an 8‐nm thick film. The current work demonstrates the potential of ALD‐grown crystalline oxides to be explored for advanced electronic applications, including high‐mobility Ge‐based transistors.     

原子层沉积生长速率的控制研究进展

原子层沉积生长技术(ALD)是以表面自限制化学反应为机制的薄膜沉积技术, 可以一层一层地生长薄膜。该技术具有生长温度低、沉积厚度精确可控、保形性好和均匀性高等优点, 逐渐成为制备薄膜材料最具发展潜力的薄膜生长技术。作为ALD技术中一个关键的指标--生长速率, 不仅对沉积所得薄膜的晶体质量、致密度起重要作用, 更重要的是影响集成电路的生产效率。本文综述了近年来ALD生长机制和生长速率方面的研究结果, 以及ALD技术生长速率的影响因素, 并分析探讨了提高和改善ALD生长速率的方法以及研究趋势。     

原子层沉积技术及其在半导体中的应用

首先简述原子层沉积（ALD）技术的发展背景，通过分析ALD的互补性和自限制性等工艺基础，介绍了它在膜层的均匀性、保形性以及膜厚控制能力等方面的优势，着重列举ALD在半导体互连技术、高k电介质等方面的应用。同时指出了目前ALD工艺中存在的主要问题。