基于神经网络的AZO薄膜制备工艺参数的正交优化设计

采用磁控溅射法制备AZO薄膜,研究和讨论了溅射功率、溅射时间和溅射气压3个工艺参数对AZO薄膜光学和电学性能的影响。采用正交优化设计,对3个工艺参数进行优化,测量了透射率和电阻率,以此作为薄膜光电性能的评价指标,通过极差值分析确定了制备薄膜的最佳工艺参数。影响薄膜透射率的最主要因素为溅射气压;影响电阻率的最主要因素为溅射时间。获得制备高透射率低电阻率的AZO薄膜的最佳工艺组合方案为溅射功率为400W、溅射时间为1000s、溅射气压为1.0Pa。将反馈型(BP)神经网络应用于磁控溅射AZO薄膜光学性能(可见光区的平均透射率)和电学性能(电阻率)的研究。输入样品数据对神经网络进行训练,建立AZO薄膜光电性能随溅射参数变化的预测模型。     

溅射功率对InZnO薄膜晶体管电学性能的影响研究北大核心CSCD

采用射频磁控溅射法,在室温下Si/SiO_(2)衬底上制备InZnO薄膜晶体管,并研究不同溅射功率(25,50,75和100 W)对InZnO薄膜晶体管电学性能的影响。XRD表征结果表明,不同溅射功率制备的InZnO薄膜均出现晶面为(002)面的多晶态结构。通过电学特性研究发现,当溅射功率为50 W时,电流的开关比为3×10^(7),场效应迁移率为14.8 cm^(2)V^(-1)s^(-1),阈值电压为0.82 V,亚阈值摆幅为0.38 V decade^(-1),界面缺陷态密度为1.1×10^(12)cm^(-2)eV^(-1)等获得最佳器件参数。这是因为功率50 W时用原子力显微镜测得InZnO薄膜表面粗糙度为0.86 nm,说明薄膜的表面比较平滑,表面缺陷密度较少,使InZnO薄膜沟道层和源漏电极形成了良好的接触。此外,XPS结果表明,当溅射功率为50 W时,能够有效控制氧空位缺陷,最终有效改善和提高InZnO薄膜晶体管的电学性能。     

直流溅射工艺参数对Mo薄膜结构及电性能的影响

采用直流磁控溅射法在SLG衬底上沉积Mo薄膜,对不同溅射功率和溅射工作气压下沉积的薄膜进行X射线衍射、SEM(扫描电子显微镜)、电阻率测试,讨论了工艺参数对沉积Mo薄膜相结构、表面微观形貌、薄膜沉积速率和电学性能的影响。结果表明,随着溅射功率的增加,薄膜的结晶性能变好,沉积速率提高,在沉积功率范围内薄膜均匀致密,表面无空隙,电阻率较低;随着溅射工作气压增加,薄膜结晶性能变差,沉积速率先增加后降低,在沉积工作气压范围内,薄膜致密;随气压降低,电阻率急剧减小。因此,较高的溅射功率和较低的工作气压沉积的Mo薄膜更适合作CIGS薄膜太阳电池的BC层(背接触层)。     

溅射功率对ZnO：Si透明导电薄膜性能的影响

采用直流磁控溅射法在室温玻璃基片上制备出了掺硅氧化锌（ZnO：Si）透明导电薄膜,研究了溅射功率对ZnO：Si薄膜结构、形貌、光学及电学性能的影响,实验结果表明,溅射功率对ZnO：Si薄膜的生长速率、结晶质量及电学性能有很大影响,而对其光学性能影响不大。实验制备的ZnO：LSi薄膜为六方纤锌矿结构的多晶薄膜,且具有垂直于基片方向的c轴择优取向。当溅射功率从45W增加到105W时,薄膜的晶化程度提高、晶粒尺寸增大,薄膜的电阻率减小;当溅射功率为105W时,薄膜的电阻率达到最小值3．83~104n·cm,其可见光透过率为94．41％。实验制备的ZnO：Si薄膜可以用作薄膜太阳能电池和液晶显示器的透明电极。     

磁控溅射中工艺参数对ZnO:Al薄膜性能的影响

利用射频磁控溅射法,采用氧化锌铝(98%ZnO+2%Al2O3)为靶材,在普通载玻片上制备了ZAO(ZnO∶Al)薄膜,研究了溅射功率及溅射气压对薄膜晶体结构、电学和光学性能的影响.采用X射线衍射仪、场扫描电镜对薄膜的结构及表面形貌进行了分析,采用分光光度计和电阻率测试仪对薄膜的光电学性能进行了测试.结果表明,当溅射功率为120W、衬底温度为300℃、工作气压为0.5Pa时制得的薄膜具有良好的光电学性能,可见光平均透过率为88.21%,电阻率为8.28×10-4Ω·cm.     

磁控溅射与硫化热处理制备β-In_2S_3薄膜及光电性能

采用磁控溅射预制In薄膜和硫化热处理工艺制备了性能优良的β-In2S3薄膜。应用XRD、拉曼光谱仪及UV-Vis测试仪对薄膜的品质进行了分析,并测试了薄膜的光学与电学性能。结果表明,溅射功率和硫化热处理温度是影响薄膜品质的主要因素,比较合适的溅射功率为100~140 W,硫化热处理温度为450℃,过高的热处理温度容易在薄膜中形成缺陷,在薄膜生长过程中容易产生In5S4杂相,相比之下,溅射气体压强对薄膜品质的影响较小,溅射气体压强可选择在0.4~0.6Pa。光学与电学性能测试结果指出,得到的β-In2S3薄膜具有良好的光谱透过率,属n型半导体,可用于太阳能电池缓冲层。     

铝锆共掺杂氧化锌透明导电薄膜的低温制备及特性研究

利用直流磁控溅射法在室温玻璃衬底上制备出了可见光透过率高、电阻率低的铝锆共掺杂氧化锌(ZAZO)透明导电薄膜。讨论了溅射功率对ZAZO薄膜结构、形貌和光电性能的影响。实验结果表明,溅射功率对ZAZO薄膜的结构、形貌和电学性能有很大影响,而对其光学性能影响不大。扫描电子显微镜和X射线衍射仪研究结果表明,ZAZO薄膜为六方纤锌矿结构的多晶薄膜,具有垂直于衬底方向的c轴择优取向。当溅射功率为120 W时,薄膜的电阻率达到最小值5.28×10-4Ω.cm,其可见光区平均透过率超过94%。     

磁控溅射制备Al_2O_3薄膜及耐蚀性能研究

采用直流磁控溅射镀膜技术以高纯铝为靶材,氧气为反应气体,在304不锈钢基底上以不同溅射功率(60,90,120,150和180 W)沉积Al_2O_3薄膜。采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对薄膜晶体结构和表面形貌进行分析表征,使用电化学工作站考察Al_2O_3薄膜的耐蚀性能。结果表明:所制备的Al_2O_3薄膜表面平整、均匀致密,并且在(217)面具有较好的择优取向;溅射功率对薄膜耐蚀性有较大影响,随溅射功率增加,耐蚀性先增强后减弱,在功率为150 W时所制备薄膜的耐蚀性能最优。     

直流磁控溅射功率对溅射生长GZO薄膜光电性能的影响

本文采用直流磁控溅射沉积系统在玻璃基底上沉积镓掺杂氧化锌(GZO)薄膜,将溅射功率从120W调整到240W,步长为30W,研究功率变化对GZO薄膜的晶体结构、表面形貌、光学性能和电学性能的影响。结果表明,溅射功率对GZO薄膜电阻率有显著的影响。溅射功率为210W时薄膜呈现最低电阻率为3.31×10~(-4)Ω·cm,可见光波段平均光学透光率接近84%。随着溅射功率的增加,薄膜表面形貌和生长形态发生较大变化,并直接得到具有一定凸凹不平的微结构,GZO薄膜的致密性先增加后降低。     

功率和退火对磁控溅射生长ZnO∶Ga薄膜的影响

采用射频磁控溅射法在玻璃衬底上制备了ZnO∶Ga透明导电薄膜(GZO)。通过X射线衍射(XRD)、四探针电导率测试、紫外可见分光光度等表征方法研究了溅射功率对薄膜结晶特性及光电性能的影响。结果表明:当溅射功率180W时制备的GZO薄膜光电性能最优,方块电阻为9.8Ω/sq,电阻率为8.6×10-4Ω·cm,霍尔迁移率为12.5cm2/V·s,载流子浓度为5.8×1020cm-3,可见光透过率超过92%。另外,研究了最优制备条件下的GZO薄膜的高温稳定性,在氩气、氧气和真空气氛下分别对薄膜进行退火处理。结果表明,氩气退火的薄膜电学性能显著提高,是显著改善GZO薄膜性能的有效方法之一;氧气退火不利于薄膜的导电性;真空退火介于两者之间。     

Potential sputtering

The potential energy stored in multiply charged ions is liberated when the ions recombine during impact on a solid surface. For certain target species this can lead to a novel form of ion-induced sputtering, which, in analogy to the usual kinetic sputtering, has been termed 'potential sputtering'. This sputtering process is characterized by a strong dependence of the observed sputtering yields on the charge state of the impinging ion and can take place at ion-impact energies well below the kinetic sputtering threshold. We summarize a series of recent careful experiments in which potential sputtering has been investigated for hyperthermal highly charged ions' impact on various surfaces (e.g. Au, LiF, NaCl, SiO(2), Al(2)O(3) and MgO), present the different models proposed to explain the potential sputtering phenomenon and also discuss possible applications of potential sputtering for nanostructure fabrication.     

Application of high-density plasma to sputtering and reactive sputtering processes

An investigation of thin-film preparation processes by sputtering technique has been carried out utilizing the high-density plasma induced by the microwave power coupled in the surface wave mode. The high sputtering rate arising from the high ion current to the target is expected to be advantageous for processes of nitride surface and compounds. An independent control of the external bias potential to the target and of the gas mixture ratio is demonstrated to be possible by the mode-locking mechanism. Ferromagnetic films of FeNi alloy were deposited on glass substrates. Films of TiN and of AlN were produced on plastic substrates and on glasses.     

Transport theories of sputtering

The use of linear transport theory to calculate several observable quantities in the sputtering process is reviewed. The basic equations previously solved in the literature to obtain the sputtering yield and the energy spectra of sputtered atoms are re-derived and briefly analysed. Comparison with experiments and comments on limitations of theoretical models are included.     

Dry etching and sputtering

Dry etching is an important process for micro- and nanofabrication. Sputtering effects can arise in two contexts within a dry-etch process. Incoming ions cause removal of volatile products that arise from the interaction between the dry-etch plasma and the surface to be etched. Also, the momentum transfer of an incoming ion can cause direct removal of the material to be etched, which is undesirable as it can cause electrical or optical damage to the underlying material. This is largely avoided in dry-etch processes by use of reactive chemistries, although in some processes this component of the etching can be significant. Etch processes, both machine type and possible etch chemistries, are reviewed. Methods of characterizing the electrical and optical damage related to ion impact at the substrate are described. The use of highly reactive chemistries and molecular constituents within the plasma is best for reducing the effects of damage.     

Molecular-dynamics simulations of sputtering

The use of molecular-dynamics simulations to understand the ejection processes of particles from surfaces after energetic ion bombardment is discussed. Substrates considered include metals, covalent and ionic materials, polymers and molecular solids. It is shown how the simulations can be used to aid interpretation of experimental results by providing the underlying mechanisms behind the ejection processes.     

Influence of manufacturing process of indium tin oxide sputtering targets on sputtering behavior

Thin films of In₂O₃+SnO₂ (indium tin oxide or ITO) have wide utility because they are electrically conductive and transparent at visible wavelengths. A preferred method for making highest quality ITO coatings is reactive sputtering from targets of mixed indium and tin oxides. The resulting film properties are highly dependent upon the deposition conditions, and upon post-deposition film treatments. Film data and sputtering efficiency are also effected by sputtering target characteristics.

This study evaluated the influence of the targets on the electrical resistivity of deposited ITO films, and the effect of target properties on the sputtering rate. A matrix of 12 targets was tested; all had composition 90 wt.%In₂O₃+10 wt.%SnO₂. The effects of varying target density, degree of target oxide reduction from complete stoichiometry, and target purity were measured.

The results are, in summary, (1) partial reduction of oxide targets from complete stoichiometry does not influence film resistivity, (2) the data indicate a small (perhaps negligible) dependence of film resistivity upon target density, (3) higher target density tends to promote enhanced deposition rate, and (4) purposeful addition of silicon, aluminum, magnesium, calcium, and sodium at high levels to ITO targets degrades film resistivity depending upon the total concentration of impurities added, but independently of the contaminating species.     

Rf magnetron sputtering of polypropylene

Radio frequency magnetron sputtering of polypropylene (PP) using argon as a working gas was applied in order to prepare organic films. Changes of the structure and morphology of the PP target and sputtered films have been investigated by infrared spectroscopy, AFM and scanning electron microscopy. It has been shown that the sputtered films are hydrocarbon plasma polymers. The increased incorporation of OH groups into the deposited films was found as a consequence of the PP target history.