多层结构铁电薄膜的I—V特性性能的研究

为ＦＲＡＭ、ＦＦＥＴ和ＦＤＭ的实际应用研究，提出了多层结构铁电薄膜的设计思想，实际制备了Ｍ／ＢＩＴ／ｐ－Ｓｉ、Ｍ／ＰＺＴ／ＢＩＴ／ｐ－Ｓｉ、Ｍ／ＢＩＴ／ＰＺＴ／ＢＩＴ／ｐ－Ｓｉ三种结构铁电薄膜，并测量了它们的Ｉ－Ｖ特性曲线。结果表明，夹层结构铁电薄膜Ｍ／ＢＩＴ／ＰＺＴ／ＢＩＴ／ｐ－Ｓｉ漏电流密度Ｊ最小，在５００ｎｍ厚时Ｊ＋（＋３Ｖ）约２．８×１０－１０Ａ／ｍｍ２，Ｊ－（－３Ｖ）约１．２×１０－１２Ａ／ｍｍ２优于单层和双层结构铁电薄膜的结果。     

BaRuO3电阻薄膜制备技术

ＭＲｕＯ３系电阻薄膜是高热稳定的电阻薄膜材料。本文介绍用高频反应溅射制备ＢａＲｕＯ３电阻薄膜技术。并用电镜、ｘ－射线衍射仪、多功能电子能谱仪观察测得ＢａＲａＯ３薄膜的形貌、晶体结种、组成。结果表明：高频反应溅射制备的ＢａＲｕＯ３薄膜为六方结构（１１０）取向的多晶薄膜，由高低温下的电阻测定表明，该膜质有稳定的电阻温度系数和高温热稳定性能，是理想的发热电阻材料。     

CSD法制备PZT/Bi2Ti2O7薄膜的研究

用化学溶液分解（ＣＳＤ）法制备Ｐｂ（Ｚｒ０．５Ｔｉ０．５）Ｏ３（ＰＺＴ）和Ｂｉ２Ｔｉ２Ｏ７薄膜,利用Ｘ－射线衍射技术研究了以Ｂｉ２Ｔｉ２Ｏ７为籽晶层的ＰＺＴ薄膜的结晶性。实验结果表明,以高（１１１）取向的Ｂｉ２Ｔｉ２Ｏ７为籽晶层可获得高结晶性的ＰＺＴ薄膜,在７５０℃退火１０ｍｉｎ的ＰＺＴ／Ｂｉ２Ｔｉ２Ｏ７薄膜具有单一的钙钛矿相。     

利用CBE技术在Si衬底上生长GaAs薄膜

采用化学束外延（ＣＢＥ）技术，以三乙基镓（ＴＥＧ）和砷烷（ＡｓＨ３）为源，在Ｓｉ（００１）衬底上生长ＧａＡｓ薄膜．利用Ｈａｌｌ效应、卢瑟福背散射（ＲＢＳ）和高分辨率透射电子显微镜（ＨＲＴＥＭ）检测了外延层的质量．结果表明，ＧａＡｓ薄膜具有ｎ型导电性，载流子浓度为１．３×１０１５ｃｍ－３，其杂质估计是Ｓｉ，它来自衬底的自扩散．外延层的质量随着膜厚的增加而得到明显的改善．在ＧａＡｓ／Ｓｉ界面及其附近，存在高密度的结构缺陷，包括失配位错、堆垛层错和孪晶．这些缺陷完全缓解了ＧａＡｓ外延层和Ｓｉ衬底之间因晶格失配引     

用化学共沉SrTiO_3研制钛酸锶铋介质陶瓷

采用ＸＲＤ、ＳＥＭ、ＥＤＡＸ、粒度分析等手段研究了在（１－ｘ）ＳｒＴｉＯ３ｘＢｉ２Ｏ３·３ＴｉＯ２（简称ＳＢＴ）系统中采用化学共沉ＳｒＴｉＯ３时，Ｂｉ２Ｏ３·３ＴｉＯ２的含量对介电性能和显微结构的影响。发现当其摩尔分数ｘ小于１０％时，结构为单相固溶体，εｒ随ｘ的增加而增加；当ｘ大于１０％时，为复相结构，εｒ开始下降。这个结果与采用ＳｒＣＯ３和ＴｉＯ２固相合成的ＳｒＴｉＯ３烧块时的结果相近，变化趋势一致。但化学共沉ＳｒＴｉＯ３之晶粒细小，杂质少，故使所制介质具有非常优异的介电性能。     

Au掺杂TiO2／SiO2薄膜的光学非线性特性研究

采用溶胶－凝胶方法制备了Ａｕ掺杂的ＴｉＯ２／ＳｉＯ２复合薄膜（厚度约为１．０μｍ）。Ｘ－ｒａｙ衍射分析表明，Ａｕ的颗粒镶嵌在ＴｉＯ２／ＳｉＯ２复合薄膜的玻璃网络中。谢乐公式计算给出Ａｕ的颗粒大小约为１０ｎｍ。采用Ｚ－Ｓｃａｎ测量技术得此薄膜的光学非线性折射率为１．０９×１０－７ｅｓｕ。     

高温超导Bi2Sr1.6La0.6CuO6外延薄膜生长模式的AFM研究

利用ＡＦＭ对在（１００）和与（１００）有６°切偏角的ＳｒＴｉＯ３基片上用射频溅射方法制备的高温超导Ｂｉ２Ｓｒ１．６Ｌａ０．４ＣｕＯ６＋δ（Ｂｉ２２０１）薄膜的生长模式进行了系统地研究。对应以上两类不同切割的基片,实验观察到两种不同的薄膜生长模式。对切偏角小于０．４°的（１００）ＳｒＴｉＯ３基片,本征的生长模式是梯田岛模式（Ｖｏｌｍｅｒ－Ｗｅｂｅｒ模式）,每层的厚度为ｃ／２（１．２５ｎｍ）;在切偏角为６°的衬底上沉积的Ｂｉ２２０１薄膜则以台阶流模式（Ｓｔｅｐ－ｆｌｏｗｍｏｄｅ）生长。Ｂｉ系高温超导体的本征的二维特性决定了薄膜的生长模式。     

钛酸铋薄膜的室温脉冲激光沉积研究

在室温下,采用脉冲激光沉积（ＰＬＤ）技术在７．６２ｃｍＰｔ／Ｔｉ／ＳｉＯ２／Ｓｉ（１００）衬底上制备了钛酸铋（Ｂｉ４Ｔｉ３Ｏ１２）薄膜。Ｂｉ４Ｔｉ３Ｏ１２薄膜的厚度和组分均匀性采用卢瑟福背散射（ＲＢＳ）和扩展电阻技术（ＳＲＰ）来分析、表征;采用Ｘ射线衍射（ＸＲＤ）技术研究了薄膜的退火特性。研究发现单独用常规退火或快速退火热处理的Ｂｉ４Ｔｉ３Ｏ１２薄膜中较容易出现Ｂｉ２Ｔｉ２Ｏ７杂相;而采用常规退火和快速退火相结合的方法,较好地解决了杂相出现的问题,得到相结构和结晶性完好的Ｂｉ４Ｔｉ３Ｏ１２薄膜。透射电子显微镜实验和扩展电阻实验表明,室温下制备的Ｂｉ４Ｔｉ３Ｏ１２薄膜具有良好的表面和界面特性。     

新型陶瓷刀具材料JX—2—I组合增韧补强机理的实验研究

本文研究了新型陶瓷刀具材料ＪＸ－２－Ｉ（Ａｌ２Ｏ３／ＳｉＣｐ／ＳｉＣｗ）的力学性能，同Ａ（Ａｌ２Ｏ３），ＡＰ（Ａｌ２Ｏ３／ＳｉＣｐ），ＡＷ（Ａｌ２Ｏ３／ＳｉＣｗ）和ＪＸ－１（Ａｌ２Ｏ３／ＳｉＣｗ）材料相比，ＪＸ－２－Ｉ具有较高的抗弯强度（σｂｂ）和断裂韧性ＫＩＣ，研究结果表明，在ＪＸ－２－Ｉ陶瓷刀具材料中确实存在增韧补强原协同作用，陶瓷刀具材料ＪＸ－２－Ｉ的主要增韧机理是界面解离，裂纹偏转和晶须拔     

脉冲准分子激光PZT薄膜的制备

本实验采用脉冲准分子激光沉积（ＰＬＤ）法，在１９３ｎｍ波长，５Ｈｚ频率，４Ｊ／ｃｍ２能量密度条件下，分别在Ｓｉ（１００）和ＳｉＯ２／Ｓｉ衬底上成功地沉积Ｐｂ（Ｚｒ，Ｔｉ）Ｏ３（ＰＺＴ）薄膜，并在不同的条件下对ＰＺＴ薄膜进行退火处理。用ＸＲＤ，ＲＢＳ，ＡＳＲ等方法分别测量了薄膜的结构、组份和厚度。     

用PECVD法在金属衬底上沉积氮化硅薄膜

采用等离子体增强化学气相沉积（ＰＥＣＶＤ）方法在４０Ｃｒ钢（含Ｃｒ０．８％～１．１％）或铜等金属基片上沉积氨化硅薄膜。沉积温度为２５０℃时，制备的薄膜厚度为０．２～０．４μｍ，电阻率为８×１０￣（１６）Ω·ｃｍ，介质击穿场强达到１×１０￣７Ｖ／ｃｍ。用ＸＰＳ谱研究了薄膜的结构和成分，并分析了沉积时不同的工艺参数对薄膜绝缘耐压性能的影响。     

Smooth indium zinc oxide film prepared by sputtering a In2O3:ZnO=95:5 target

Indium zinc oxide (IZO) films with surface roughness Ra<0.3 nm have been prepared by radio frequency sputtering. The IZO film is the possible candidate for replacing the indium tin oxide (ITO) film in pattern precision or low processing temperature concern. Instead of commonly used In₂O₃:ZnO=90:10 in weight percentage (wt%) target, a target doped with 5 wt% impurities was used in this study. It was found that the electrical resistivity of the IZO film increases rapidly if oxygen gas was introduced during the sputtering process. This increase tendency in electrical resistivity is much more significant than the IZO film prepared with a 10 wt% doped ZnO target. The electrical resistivity increased rapidly as soon as the IZO film became crystallized in heat treatment. Optical properties of the IZO film do not change significantly with varying process parameters. The appropriate processing condition for the prepared IZO film is no oxygen feeding and no heat treatment.     

Si-YBaCuO intermixing and reactive patterning technique

A novel Si-YBaCuO intermixing technique has been developed for patterning YBaCuO superconducting thin films on both insulating oxide substrates (MgO) and semiconductor substrates (Si). The electrical, structural, and interfacial properties of the Si-YBaCuO intermixed system have been studied using resistivity, x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy and Auger depth profiling measurements. The study showed that the reaction of Si with YBaCuO and formation of silicon oxides during a high temperature process destroyed superconductivity of the film and created an insulating film. On a MgO substrate, the patterning process was carried out by first patterning a silicon layer using photolithography or laser-direct-writing, followed by the deposition of YBaCuO film and annealing. For a silicon substrate, thin metal layers of Ag and Au were patterned as a buffer mask which defines the YBaCuO structures fabricated thereafter. Micron-sized (2-10 Μm) superconducting structures with zero resistance temperature above 77 K have been demonstrated. This technique has been used to fabricate current controlled HTS switches and interconnects.     

薄膜厚度对直流溅射制备AZO薄膜的特性影响

采用直流磁控溅射法,当衬底温度为室温时,在普通玻璃衬底上制备出了低电阻率、高透过率的ZnO:Al透明导电薄膜.研究了薄膜厚度对薄膜结构以及光电特性影响.当薄膜厚度为930 nm,薄膜的光电特性最好,电阻率为4.65×10~(-4)Ω·cm,可见光范围内的平均透过率为85.8%,禁带宽度约为3.51 eV.     

半绝缘SiC单晶电阻率均匀性研究

采用非接触电阻率面分布(COREMA)方法对本实验室生长得到的2英寸(50 mm)4H和6H晶型半绝缘SiC单晶片进行电阻率测试,结果发现数据的离散性大,低者低于测试系统下限105Ω.cm,高者高于其上限1012Ω.cm,甚至在同一晶片内会出现小于105Ω.cm,105~1012Ω.cm和大于1012Ω.cm的不同区域,而有的晶片则电阻率的均匀性较好。将SiC电阻率测试结果与二次离子质谱(SIMS)对晶体内主要杂质V,B和N含量测试结果相结合,初步探讨得到引起掺钒SiC单晶电阻率的高低及均匀性的变化由补偿方式决定,在深受主补偿浅施主模式下,V的浓度控制在2×1016~3×1017cm-3,N的浓度控制在1×1016cm-3左右,深受主钒充分补偿浅施主氮,制备得到的SiC单晶具有半绝缘性,且电阻率均匀性好。     

Ceramic ferroelectric field effect studies

The ferroelectric field effect has been observed in a semiconducting thin film of n-type tin oxide deposited on a ferroelectric lead zirconate-titanate ceramic substrate. The semiconductor was deposited by electron gun evaporation onto a thermally depolarized (randomly oriented) substrate which permitted the carrier concentration of the film to be enhanced or depleted depending on the direction of polarization of the substrate. Typical average resistivity values of 200-Å films are approximately 0.1 Ω.cm for the depoled state, 0.01 Ω.cm for the enhanced state, and 100-1000 Ω.cm for the depleted state. "On"-"off" ratios as high as1.7 times 10^{5}have been observed in a single device. The transition from enhancement to depletion is quasi-continuous due to the small size and random orientation of the individual crystallites in the ceramic. Conductance measurements during this transition have yielded field effect mobilities in the range 7-10 cm²/V.s; and maximum average carrier densities in the range 0.5-1.0 × 10²⁰carriers/cm3. The tin oxide-ceramic devices described here suffer from the long-term drift that is characteristic of many field effect devices. The resistivity of a device stored in the depleted state will decrease from 3 to 4 orders of magnitude in times between 10⁴-10⁵minutes.     

Characterization of phosphorus implanted low pressure chemical vapor deposited polycrystalline silicon

Thin (3000–5000Å) low pressure chemically vapor deposited (LPCVD) films of polycrystalline silicon suitable for microelectronics applications have been deposited from silane at 600°C and at a pressure of 0.25 Torr. The films were phosphorus implanted at 150 KeV and electrically characterized with the annealing conditions and film thickness as parameters, over a resistivity range of four orders of magnitude (10³–10⁷Ω/□). Annealing during silox deposition was found to result in a lower film resistivity than annealing done in nitrogen atmosphere. Resistivity measurements as a function of temperature indicate that the electrical activation energy is a linear function of 1/N(N is the doping concentration), changing from 0.056 eV for a doping concentration of 8.9 × 10¹⁸ cm⁻³ to 0.310 eV for doping concentration of 3.3 × 10¹⁸ cm⁻³. The grain boundary trap density was found to have a logarithmically decreasing dependence on the polysilicon thickness, decreasing from 1.3 × 10¹³ cm⁻² for 2850Å polysilicon film to 8.3 × 10¹² cm⁻² for 4500Å polysilicon film.     

衬底温度和溅射偏压对ZnO:Al透明导电膜结构和光电特性的影响

利用射频磁控溅射法在有机薄膜衬底和7059玻璃衬底上制备出了具有良好附着性的低电阻率的 ZnO:Al透明导电膜。研究了薄膜的结构和光电特性与衬底温度的关系,薄膜为多晶纤锌矿结构,垂直于衬底的 c 轴具有[002]方向的择优取向,薄膜的最低电阻率分别为 1.01×10–3ù·cm 和 8.48×10–4ù·cm,在可见光区的平均透过率分别达到了72%和 85%。并研究了溅射偏压对有机衬底 ZnO:Al 薄膜结构及光电特性影响,最佳负偏压为 60 V。     

二氧化锡覆盖层对ITO透明导电薄膜热稳定性的改良

采用射频磁控溅射法在ITO玻璃表面沉积了一层15 nm左右的SnO2薄膜。利用霍尔效应测试仪、四探针电阻测试仪、场发射电子显微镜及紫外–可见–近红外光谱仪分析了所制薄膜的电学性质、表面形貌和光学性质。结果表明,在300~600℃退火后镀有SnO2覆盖层的ITO(SnO2/ITO)薄膜具有相对好的热学稳定性。在600℃退火后,ITO薄膜的方阻和电阻率分别为88.3Ω/□和2.5×10–3.cm,而此时,SnO2/ITO薄膜的方阻和电阻率仅为43.8Ω/□和1.2×10–3Ω.cm。最后,阐述了SnO2覆盖层提高ITO薄膜热稳定性的机制。     

Improving the electrical and mechanical behavior of electrically conductive paint by partial replacement of silver by carbon black

Partial replacement of silver particles by carbon black (low cost) in electrically conductive paint was found to decrease the electrical resistivity and increase the scratch resistance of the resulting thick film, which is for use in electrical interconnections. An effective carbon black content is 0.055 of the total filler volume. By using a total solid volume fraction of 0.1969 and a silane-propanol (1:1 by weight) solution as the vehicle, a paint that gives a thick film with resistivity 2 × 10⁻³ Ω·cm has been attained.