原子层沉积低温生长α-MoO3薄膜

以六羰基钼和氧气为前驱体,通过等离子增强原子层沉积技术（PE-ALD）在硅基片上实现了α-MoO₃薄膜的低温制备。利用X射线衍射仪、扫描电子显微镜、原子力显微镜、X射线光电子能谱仪等手段对薄膜的晶体结构、表面形貌及薄膜成分进行表征和分析。研究发现衬底温度和氧源脉冲时间对MoO₃薄膜的晶体结构和表面形貌变化起关键作用。当衬底温度为170℃及以上时所制备的薄膜为α-MoO₃;适当延长ALD单循环中的氧源脉冲时间有利于低温沉积沿（0k0）高度择优取向的MoO₃薄膜。根据对不同厚度MoO₃薄膜表面的原子力显微图片分析,MoO₃薄膜为岛状生长模式。     

有机电致发光器件的新型薄膜封装技术研究

针对有机电致发光器件(OLED)在空气中水汽和O2作用下寿命下降的问题,提出一种对OLED进行薄膜封装方法。封装薄膜由电子束蒸镀Al2O3薄膜和原子层沉积(ALD,atomic layer deposition)Al2O3薄膜相结合形成。利用Ca薄膜电学测试方法测定封装薄膜的水汽透过率(WVTR)。具体实现方法是,采用玻璃作为衬底,在100nm的Al电极上蒸镀200nm的Ca膜,然后对整个系统进行薄膜封装,只留出Al电极的一部分作为探针接触电极。实验发现,采用电子束蒸镀结合ALD的Al2O3薄膜封装,Ca薄膜变成透明的时间比未封装或采用单一结构封装得到了延长。为了检验薄膜封装效果,制作了一组绿光OLED,器件结构为ITO/MoOX(5nm)/mMTDATA(20nm)/NPB(30nm)/Alq3(50nm)/LiF(1nm)/Al,实验结果表明,本文提出的薄膜封装方法对器件进行封装,器件的寿命得到了延长。     

原子层沉积制备ZnO薄膜研究进展

随着半导体技术的发展,ZnO作为第三代半导体材料,具有禁带宽度大、载流子漂移饱和速度高和介电常数小等优点,更适合制作蓝光和紫外光的发光器件。与传统的薄膜制备技术相比,原子层沉积技术(ALD)在膜生长方面具有生长温度低、厚度高度可控、保形性好和均匀性高等优点,逐渐成为制备ZnO薄膜的主流方法。综述了ALD制备ZnO薄膜的反应机制、生长机制和掺杂方面的研究进展,针对当前ZnO薄膜p型掺杂的难点,指出了V族元素中的大半径原子(磷和砷等)掺杂有可能成为制备高质量、可重复和稳定的p型ZnO的潜力研究点,最后总结和展望了ALD制备ZnO薄膜的应用前景和研究趋势。     

硫化锌薄膜的原子层沉积生长及表征

为满足硫化锌(ZnS)薄膜在光学薄膜领域进一步应用的要求,基于原子层沉积(Atomic Layer Deposition, ALD)技术在130℃温度下以二乙基锌(DEZ)和硫化氢(H2S)为反应源,在砷化镓(GaAs)衬底表面沉积了ZnS薄膜。用扫描电子显微镜(Scanning Electron Microscope, SEM)分析了样品的表面形貌和膜界面特性,用X射线衍射仪(X-ray Diffraction, XRD)分析了薄膜的结构特性,并通过X射线光电子能谱(X-ray Photoelectron Spectroscopy, XPS)分析了薄膜的化学成分。研究了厚度对薄膜结构和形貌的影响。结果表明,得到的ZnS薄膜为多晶结构,薄膜的厚度随循环数线性增加,速率为1.45 ?/cycle。对在75℃温度下烘烤48 h后的薄膜进行了XPS分析,得出的Zn/S比为1.07:1,表明烘烤除去了薄膜中残存的H2S。以较短生长时间得到的较薄的薄膜具有更好的表面平整度和更致密的结构。     

不同深宽比GaAs衬底的Al22O3/HfO2复合薄膜材料原子层沉积及能谱分析

利用热原子层沉积（Atomic Layer Deposition, ALD）技术在不同深宽比GaAs衬底上进行了Al2₂O₃/HfO₂复合薄膜的沉积。通过对其表面和能谱进行分析发现,沉积温度对复合薄膜的摩尔比具有较大的影响。随着深宽比的增大,其沉积表面和沟槽内会出现残留物;随着ALD沉积温度的上升,其沉积表面和沟槽内的残留物减少,摩尔比趋向均匀。当深宽比为2.2并利用150 ℃的低沉积温度时,表面及底面基本无残留物。但当深宽比为4.25时,150 ℃沉积明显有大量残留物。只有当温度升高到300 ℃时,表面和沟槽里复合薄膜的残留物才被明显消除。ALD技术可以实现各种器件结构的全方位钝化,这是其他化学气相沉积法无法比拟的。     

波浪形界面结构的Al2O3/PMMA交叠薄膜设计与力学性能仿真

文章以Al₂O₃/PMMA交叠薄膜为例,在其交叠界面处引入波浪形结构,通过增加Al₂O₃在弯曲方向的实际长度改善其力学性能。采用有限元仿真方法对Al₂O₃/PMMA交叠薄膜结构进行建模,分别研究了波浪形结构形貌、周期、深度和PMMA厚度等参数对交叠薄膜弯曲性能的影响规律。仿真结果表明,波浪形界面结构能较大提高交叠薄膜的弯曲性能,当波浪形结构的周期在500～1 500 nm,深度在600～1 600 nm范围内,PMMA厚度为6μm时,交叠薄膜具有较好的弯曲性能,相比于没有引入界面结构的交叠薄膜,同等条件下产生的最大应力下降了超过70%,有效提升了封装薄膜的弯曲性能,对后续无机/有机交叠薄膜的制备工艺具有指导意义。     

基于Cs2CO3/Al结构的蓝光OLED器件

研究了碳酸铯(Cs2CO3)作为电子注入层对蓝光有机电致发光器件性能的影响。结果表明,与常用的LiF/Al结构相比,Cs2CO3/Al结构的电子注入能力更强。对Cs2CO3电子注入层的厚度进行了优化,表明Cs2CO3厚度为1.5nm时,器件的发光效率和功率效率有很大提高,在较低电流密度(13.2mA/cm2)下即达到其最大发光效率(3.04cd/A),分析得到真空蒸镀Cs2CO3能够有效提高电子注入的机理:低功函的金属Cs起到了克服肖特基势垒、增强电子注入的作用。     

热原子层沉积技术制备TiAlCN薄膜的特性

在Si和SiO2基底上,采用热原子层沉积技术,以四(二甲基氨基)钛(Ti(N (CH3)2)4)和三甲基铝(Al (CH3)3)为前驱体,制备TiAlCN薄膜.测试结果表明,随着基底温度的升高,膜层的沉积速率升高,电阻率降低,光学带隙由3.45 eV降低到2.00 eV,并在基底温度为300和350℃时出现了双吸收边;基底温度为350℃时,Al (CH3)3分解,使Al进入膜层与TiN和TiC形成TiAlN和TiAlC;膜层中TiN和TiC的形成,可以有效抑制膜层的自然氧化;基底温度为250和300℃时,薄膜为无定型结构,当基底温度为350℃时,有TiN晶体产生;膜层的表面粗糙度随着基底温度的升高先降低后升高,表面粗糙度的升高可能是因为在基底温度为350℃时前驱体材料的分解,使C-H键进入膜层所导致的.     

等离子体增强原子层沉积制备压电AlN薄膜

采用等离子体增强原子层沉积(PEALD)技术在单晶硅衬底上成功制备了具有(002)晶面择优取向的氮化铝(AlN)晶态薄膜,为设计新型压电功能器件提供了思路.利用椭圆偏振光谱仪(SE)、原子力显微镜(AFM)、X射线衍射仪(XRD)、X射线光电子能谱仪(XPS)对.样品的生长速率、表面形貌、晶体结构、薄膜成分进行了表征和分析.结果 表明,在250℃沉积温度下,以N2H2和Ar的混合气体的等离子体作为共反应物,在相同工艺条件下仅增加前驱体三甲基铝(TMA)脉冲注入之后的氮气吹扫时间(tp1),制备的AlN薄膜的(002)晶面择优取向趋于显著,说明tp1的增加可以促进Al和N原子的有序排列,并促进(002)晶面择优取向形成.实验中,tp1为30 s且循环次数为1150时,PEALD制备的AlN薄膜表面平整光滑,均方根表面粗糙度为0.885 nm,(002)晶面衍射峰最明显,薄膜中氧原子数分数为11.04％,氧原子在AlN薄膜中形成氧缺陷并形成一种稳定的基于八面体配位铝的新型氧缺陷相,XPS结果证明了N-O-Al键的形成.     

Synthesis and electromagnetic transport of large-area 2D WTe2 thin film

Tungsten telluride thin films were successfully prepared on monocrystal sapphire substrates by using atomic layer deposition and chemical vapor deposition technology, and the effects of different tellurization temperatures on the properties of tungsten telluride films were investigated. The growth rate, crystal structure and composition of the film samples were characterized and analyzed by using scanning electron microscope, Raman spectroscopy and X-ray photoelectron spectroscopy. The results showed that tungsten telluride thin films with good crystal orientation in (001) were obtained at telluride temperature of 550 °C. When the telluride temperature reached 570 °C, the tungsten telluride began to decompose and unsaturated magnetoresistance was found.     

具有SiO2/SiNX/SiO2 复合绝缘层的有机薄膜晶体管

We have investigated a SiO_2/SiN_x/SiO_2 composite insulation layer structured gate dielectric for an organic thin film transistor(OTFT) with the purpose of improving the performance of the SiO_2 gate insulator. The SiO_2/SiN_x/SiO_2 composite insulation layer was prepared by magnetron sputtering.Compared with the same thickness of a SiO_2 insulation layer device,the SiO_2/SiN_x/SiO_2 composite insulation layer is an effective method of fabricating OTFT with improved electric characteristics and decrease...     

Top gate ZnO-Al2O3 thin film transistors fabricated using a chemical bath deposition technique

ZnO thin films were prepared by a simple chemical bath deposition technique using an inorganic solution mixture of ZnCl₂ and NH₃ on glass substrates and then were used as the active material in thin film transistors (TFTs). The TFTs were fabricated in a top gate coplanar electrode structure with high-k Al₂O₃ as the gate insulator and Al as the source, drain and gate electrodes. The TFTs were annealed in air at 500 ℃ for 1 h. The TFTs with a 50 μm channel length exhibited a high field-effect mobility of 0.45 cm²/(V·s) and a low threshold voltage of 1.8 V. The sub-threshold swing and drain current ON-OFF ratio were found to be 0.6 V/dec and 10⁶, respectively.     

Highly-impermeable Al2O3/HfO2 moisture barrier films grown by low-temperature plasma-enhanced atomic layer deposition

Polymer substrates are essential components of flexible electronic applications such as OTFTs, OPVs, and OLEDs. However, high water vapor permeability of polymer films can significantly reduce the lifetime of flexible electronic devices. In this study, we examined the water vapor permeation barrier properties of Al₂O₃/HfO₂ mixed oxide films on polymer substrates. Al₂O₃/HfO₂ films deposited by plasma-enhanced atomic layer deposition were transparent, chemically stable in water and densely amorphous. At 60 °C and 90% relative humidity (RH) accelerated condition, 50-nm-thick Al₂O₃/HfO₂ had water vapor transmission rate (WVTR) = 1.44 × 10⁻⁴ g m⁻² d⁻¹, whereas single layers of Al₂O₃ had WVTR = 3.26 × 10⁻⁴ g m⁻² d⁻¹ and of HfO₂ had WVTR = 6.75 × 10⁻² g m⁻² d⁻¹. At 25 °C and 40% RH, 50-nm-thick Al₂O₃/HfO₂ film had WVTR = 2.63 × 10⁻⁶ g m⁻² d⁻¹, which is comparable to WVTR of conventional glass encapsulation.     

原子层沉积氧化铝薄膜对多晶太阳能电池表面钝化的影响

A stack of Al2O3/SiNx dual layer was applied for the back side surface passivation of p-type multi-crystalline silicon solar cells, with laser-opened line metal contacts, forming a local aluminum back surface field （local Al-BSF） structure. A slight amount of Al2O3, wrapping around to the front side of the wafer during the thermal atomic layer deposition process, was found to have a negative influence on cell performance. The different process flow was found to lead to a different cell performance, because of the Al2O3 wrapping around the front surface. The best cell performance, with an absolute efficiency gain of about 0.6% compared with the normal full Al-BSF structure solar cell, was achieved when the Al2O3 layer was deposited after the front surface of the wafer had been covered by a SiNx layer. We discuss the possible reasons for this phenomenon, and propose three explanations as the Ag paste, being hindered from firing through the front passivation layer, degraded the SiNx passivation effect and the Al2O3 induced an inversion effect on the front surface. Characterization methods like internal quantum efficiency and contact resistance scanning were used to assist our understanding of the underlying mechanisms.     

Fabrication of tunable [Al2O3:Alucone] thin-film encapsulations for top-emitting organic light-emitting diodes with high performance optical and barrier properties

The optical and barrier properties of thin-film encapsulations (TFEs) for top-emitting organic light-emitting diodes (TEOLEDs) were investigated using TFEs fabricated by stacking multiple sets of inorganic–organic layers. The inorganic moisture barrier layers were prepared by atomic layer deposition (ALD) of Al₂O₃ using trimethylaluminum (TMA) and O₃ as precursors and are shown to be efficient barriers against gases and vapors. The organic alucone layers were produced by molecular layer deposition (MLD) using TMA and ethylene glycol as precursors. The [Al₂O₃:Alucone] ALD/MLD films were used because their adjustable inorganic–organic nanolaminate composition allows for the tuning of the optical properties, thereby enhancing their application potential for the design and fabrication of high performance light out-coupling structures for TEOLEDs. By carefully adjusting the relative thickness ratio of the inorganic–organic encapsulation materials, optimized light extraction was achieved and the films not only maintained their high moisture barrier strength but also showed excellent optical performance.     

Organic thin film transistors with a SiO2/SiNx/SiO2 composite insulator layer

We have investigated a SiO₂/SiN_x/SiO₂ composite insulation layer structured gate dielectric for an organic thin film transistor（OTFT） with the purpose of improving the performance of the SiO₂ gate insulator. The SiO₂/SiN_x/SiO₂ composite insulation layer was prepared by magnetron sputtering.Compared with the same thickness of a SiO₂ insulation layer device,the SiO₂/SiN_x/SiO₂ composite insulation layer is an effective method of fabricating OTFT with improved electric characteristics and decreased leakage current.Electrical parameters such as carrier mobility by field effect measurement have been calculated.The performances of different insulating layer devices have been studied,and the results demonstrate that when the insulation layer thickness increases,the off-state current decreases.     

Interface composition of atomic layer deposited HfO2 and Al2O3 thin films on InAs studied by X-ray photoemission spectroscopy

We present a synchrotron-based XPS investigation on the interface between InAs and Al₂O₃ or HfO₂ layers, deposited by ALD at different temperatures, for InAs substrates with different surface orientations as well as for InAs nanowires. We reveal the composition of the native Oxide and how the high-κ layer deposition reduces Oxide components. We demonstrate some of the advantages in using synchrotron radiation revealing the variation in Oxide composition as a function of depth into the subsurface region and how we can indentify Oxides even on nanowires covering only a small fraction of the surface.     

Si/Al2O3/ZnO:Al capacitor arrays formed in electrochemically etched porous Si by atomic layer deposition

High surface area Si/Al₂O₃/ZnO:Al capacitors were formed in electrochemically etched porous silicon. The Al₂O₃ dielectric and the ZnO:Al top electrode were deposited by atomic layer deposition in high aspect ratio porous Si. A single capacitor with a typical area of about 1 mm² consisted of about 10⁵ pores. Effective capacitance densities were between 2.0 and 2.5 μF/cm², i.e., approximately 30 times higher than for a planar capacitor prepared under identical conditions, illustrating the effect of the enhanced surface area in the porous structure.     

原子层沉积薄膜之激光损伤性能分析

采用目前尚在国内鲜有报道的原子层沉积技术在熔石英和BK7玻璃基片上镀制了TiO2单层膜、AlO3单层膜以及TiO2/Al2O3增透膜,沉积温度在110℃和280℃.利用X射线粉末衍射仪对膜层微观结构进行了分析研究,并在激光损伤平台上进行了抗激光损伤阈值的测量.采用Nomarski微分干涉差显微镜和原子力显微镜对激光损伤...