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In this work atomic layer deposition of Al2O3 and TiO2 has been used to obtain dielectric stacks for passivation of silicon surfaces. Our experiments on n‐ and p‐type silicon wafers deposited by thin Al2O3/TiO2 stacks show that a considerably improved passivation is obtained compared to the Al2O3 single layer. For Al2O3 films thinner than 20 nm the emitter saturation current density decreases with increasing TiO2 thickness. Especially the passivation of ultrathin (~5 nm) Al2O3 is very effectively enhanced by TiO2 due to a decreased interface defect density as well as an increased fixed negative charge in the stacks. Hence, the thin Al2O3/TiO2 stacks developed in this work can be used as a passivation coating for Si‐based solar cells. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

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We investigate the effect of O3 and H2O oxidant pre‐pulse prior to Al2O3 atomic layer deposition for Si surface passivation. Interfacial oxide SiOx formed by the O3 pre‐pulse is more beneficial than that by H2O to a high level of surface passivation. The passivation of thinner H2O–Al2O3 films is more improved by this O3 pre‐pulse. O3 pre‐pulse for 10 nm H2O–Al2O3 reduces saturation current density in boron emitter to 18 fA cm–2 by a factor of 1.7. Capacitance–voltage measurements reveal this interfacial oxide plays a role of decreasing interface trap density without detrimental effect to negative charge density of Al2O3. (© 2014 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)  相似文献   

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樊继斌  刘红侠  段理  张研  于晓晨 《中国物理 B》2017,26(6):67701-067701
A comparative study of two kinds of oxidants(H_2O and O_3) with the combination of two metal precursors(TMA and La(~iPrCp)_3) for atomic layer deposition(ALD) La_2O_3/Al_2O_3 nanolaminates is carried out. The effects of different oxidants on the physical properties and electrical characteristics of La_2O_3/Al_2O_3 nanolaminates are studied. Initial testing results indicate that La_2O_3/Al_2O_3 nanolaminates could avoid moisture absorption in the air after thermal annealing. However, moisture absorption occurs in H_2O-based La_2O_3/Al_2O_3 nanolaminates due to the residue hydroxyl/hydrogen groups during annealing. As a result, roughness enhancement, band offset variation, low dielectric constant and poor electrical characteristics are measured because the properties of H_2O-based La_2O_3/Al_2O_3 nanolaminates are deteriorated. Addition thermal annealing effects on the properties of O_3-based La_2O_3/Al_2O_3 nanolaminates indicate that O_3 is a more appropriate oxidant to deposit La_2O_3/Al_2O_3 nanolaminates for electron devices application.  相似文献   

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The (NH4)2S treatment can reduce native oxides and passivate GaAs. Atomic‐layer‐deposited (ALD‐Al2O3) can further remove the residue native oxides by self‐cleaning. For the first time, native oxides can be sufficiently removed by the combination of (NH4)2S treatment and ALD‐Al2O3. Stacked with high dielectric constant TiO2 prepared by atomic‐layer deposition on a Al2O3/(NH4)2S‐treated GaAs MOS capacitor, the leakage current densities can reach 1.9 × 10−8 and 3.1 × 10−6 A/cm2 at ±2 MV/cm. The dielectric constant is 25 and the interface state density is about 2.4 × 1011 cm−2 eV−1.  相似文献   

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张祥  刘邦武  夏洋  李超波  刘杰  沈泽南 《物理学报》2012,61(18):442-450
介绍了A1203的材料性质及其原子层沉积制备方法,详细阐述了该材料的钝化机制(化学钝化和场效应钝化),并从薄膜厚度、热稳定性及叠层钝化等角度阐释其优化方案.概述了Al203钝化在晶体硅太阳电池中的应用,主要包括钝化发射极及背面局部扩散电池和钝化发射极及背表面电池.最后,对A1203钝化工艺的未来研究方向和大规模的工业应用进行了展望.  相似文献   

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董亚斌  夏洋  李超波  卢维尔  饶志鹏  张阳  张祥  叶甜春 《物理学报》2013,62(14):147306-147306
介绍了新型材料ZnO的各项性能,并采用原子层沉积方法制备新型材料ZnO. 实验中采用二乙基锌(DEZn) 和水作为生长ZnO的前驱体源, 在蓝宝石衬底上生长ZnO; 采用氮气作为载气, 生长温度为180℃. 通过改变在实验中的通入锌源的时间, 探索不同的DEZn的源的量对薄膜的成分(Zn/O)、薄膜的厚度、生长速率、晶型、 表面形貌、三维形貌以及粗糙度的影响.关键词:氧化锌原子层沉积Zn/O  相似文献   

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闫大为  李丽莎  焦晋平  黄红娟  任舰  顾晓峰 《物理学报》2013,62(19):197203-197203
利用原子层沉积技术制备了具有圆形透明电 极的Ni/Au/Al2O3/n-GaN金属-氧化物-半导体结构, 研究了紫外光照对样品电容特性及深能级界面态的影响, 分析了非理想样品积累区电容随偏压增加而下降的物理起源. 在无光照情形下, 由于极长的电子发射时间与极慢的少数载流子热产生速率, 样品的室温电容-电压扫描曲线表现出典型的深耗尽行为, 且准费米能级之上占据深能级界面态的电子状态保持不变. 当器件受紫外光照射时, 半导体耗尽层内的光生空穴将复合准费米能级之上的深能级界面态电子, 同时还将与氧化层内部的深能级施主态反应. 非理想样品积累区电容的下降可归因于绝缘层漏电导的急剧增大, 其诱发机理可能是与氧化层内的缺陷态及界面质量有关的“charge-to-breakdown”过程.关键词:原子层沉积2O3/n-GaN')\" href=\"#\">Al2O3/n-GaN金属-氧化物-半导体结构电容特性  相似文献   

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原子层沉积氧化铝已经成为应用于钝化发射极和背面点接触(PERC)型晶硅太阳能电池优异的钝化材料.对于基于丝网印刷技术的太阳能电池,钝化材料的钝化效果及其热稳定性是非常重要的.本文在太阳能级硅片上用热原子层沉积设备制备了20nm和30nm的氧化铝,少子寿命测试结果显示初始沉积的氧化铝薄膜具有一定的钝化效果,在退火后可达到100μs以上,相当于硅表面复合速度小于100cm/s.经过制备传统晶硅太阳能电池的烧结炉后,少子寿命能够保持在烧结前的一半以上,可应用于工业PERC型电池的制备.通过电子显微镜观察到了较厚的氧化铝薄膜有气泡,解释了30nm氧化铝比20nm氧化铝钝化性能和稳定性更差的异常表现.  相似文献   

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樊继斌  刘红侠  孙斌  段理  于晓晨 《中国物理 B》2017,26(5):57702-057702
La-based binary or ternary compounds have recently attracted a great deal of attention as a potential candidate to replace the currently used Hf-based dielectrics in future transistor and capacitor devices for sub-22 generation. However, the hygroscopic nature of La2O3 hampers its application as dielectrics in electron devices. To cope with this challenge, ultraviolet (UV) ozone post treatment is proposed to suppress the moisture absorption in the H2O-based atomic layer deposition (ALD) La2O3/Al2O3 nanolaminates which is related to the residual hydroxyl/hydrogen groups after annealing. The x-ray photoelectron spectroscopy (XPS) and conductive atomic force microscopy (AFM) results indicate that the moisture absorption of the H2O-based ALD La2O3/Al2O3 nanolaminates is efficiently suppressed after 600 ℃ annealing, and the electrical characteristics are greatly improved.  相似文献   

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Silicon solar cells passivated with Al2O3 require a capping layer that protects the passivation layer from humidity because of sensitivity of Al2O3 to moisture. Al2O3/TiO2 stacks obtained by atomic layer deposition have been known to provide a high level of passivation layers because of their excellent field‐effect passivation. In this work, degradation of this Al2O3/TiO2 stack, when exposed to humidity, is examined, and an attempt is made for a humidity‐resistant encapsulation layer by adding Al2O3/TiO2 nanolaminates that can be deposited in‐situ without breaking vacuum. Placing the nanolaminate on top of the TiO2 and Al2O3 stack is found to lead to almost no degradation even after 10 days of humidity exposure. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)  相似文献   

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Atomic-layer-deposited(ALD) aluminum oxide(Al_2O_3) has demonstrated an excellent surface passivation for crystalline silicon(c-Si) surfaces, as well as for highly boron-doped c-Si surfaces. In this paper, water-based thermal atomic layer deposition of Al_2O_3 films are fabricated for c-Si surface passivation. The influence of deposition conditions on the passivation quality is investigated. The results show that the excellent passivation on n-type c-Si can be achieved at a low thermal budget of 250℃ given a gas pressure of 0.15 Torr. The thickness-dependence of surface passivation indicates that the effective minority carrier lifetime increases drastically when the thickness of Al_2O_3 is larger than 10 nm. The influence of thermal post annealing treatments is also studied. Comparable carrier lifetime is achieved when Al_2O_3 sample is annealed for 15 min in forming gas in a temperature range from 400℃ to 450℃. In addition, the passivation quality can be further improved when a thin PECVD-SiN_x cap layer is prepared on Al_2O_3, and an effective minority carrier lifetime of2.8 ms and implied Voc of 721 mV are obtained. In addition, several novel methods are proposed to restrain blistering.  相似文献   

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伦志远  李云  赵凯  杜刚  刘晓彦  王漪 《中国物理 B》2016,25(8):88502-088502
In this work, the trap-assisted tunneling(TAT) mechanism is modeled as a two-step physical process for charge trapping memory(CTM). The influence of the TAT mechanism on CTM performance is investigated in consideration of various trap positions and energy levels. For the simulated CTM structure, simulation results indicate that the positions of oxide traps related to the maximum TAT current contribution shift towards the substrate interface and charge storage layer interface during time evolutions in programming and retention operations, respectively. Lower programming voltage and retention operations under higher temperature are found to be more sensitive to tunneling oxide degradation.  相似文献   

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This value is achieved due to a very low interface trap density of below 1010 eV–1 cm–2 and a fixed charge density of (2–3) × 1012 cm–2. In contrast, plasma ALD‐grown Al2O3 layers only reach carrier lifetimes of about 1 ms. This is mainly caused by a more than 10 times higher density of interface traps, and thus, inferior chemical passivation. The strong influence of the deposition parameters is explained by the limitation of hydrogen transport in Al2O3 during low‐thermal budget annealing. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)  相似文献   

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