SmCo磁记录薄膜中磁耦合作用的研究

采用磁控溅射方法,在玻璃基片上制备了Cr/SmCo/Cr结构的SmCo薄膜,实验结果表明:在低Sm含量(20.5%(原子分数))和高Sm含量(大于30.7%)的SmCo薄膜中都能形成SmCO_5磁性相,在Sm含量较高的SmCo薄膜中同时还形成了SmCo_2等非磁性相,非磁性相的存在对磁性相有隔离作用,从而降低了磁性晶粒之间的磁耦合作用.因此可以用提高Sm含量的方法来降低SmCo薄膜磁性晶粒之间的磁耦合作用.     

低介电常数介质薄膜的研究进展

用低介电常数介质薄膜作金属线间和层间介质可以降低超大规模集成电路(ULSI) 的互连延迟、串扰和能耗。从介质极化的原理出发,揭示了开发低介电常数介质薄膜的可能途径;综述了低介电常数介质薄膜的制备方法、结构与性能表征、工艺兼容性等领域的最新进展。     

表面镀覆技术——化学镀的进展

本文综述了表面镀覆技术——化学镀的发展史，工艺技术的优越性，技术关键所在，以及它的发展现状和应用前景     

SiO2/SiNx:H选择性刻蚀改善光诱导化学镀/电镀多晶硅太阳能电池过镀现象

自对准的光诱导化学镀/电镀技术以其栅线宽度小、工艺快捷高效等优点, 成为制备选择性发射极太阳能电池的理想选择. 然而, 该技术的前序需要HF溶液有效去除重掺杂区表面SiO₂的同时, 避免在SiNx:H掩模上刻蚀出微孔而露出衬底的硅, 否则金属镍和银会在光诱导化学镀/电镀工艺中沉积在微孔中, 导致过镀现象. 这就要求预处理溶液对SiO₂/SiNx:H有很高的选择性刻蚀. 本工作根据实验结果分析了产生过镀现象的原因, 研究了进行SiO₂/SiNx:H选择性刻蚀的可行性. 依据HF刻蚀SiO₂和SiNx:H的机理, 通过调节HF缓释溶液的pH值, 改善了多晶硅太阳能电池的过镀现象.     

化学镀钴和超级化学镀填充的研究进展

随着半导体集成度的不断提高,铜互连线的电阻率迅速提高。当互连线宽度接近7 nm时,铜互连线的电阻率与钴接近。IBM和美国半导体公司（ASE）已经使用金属钴取代铜作为下一代互连线材料。然而,钴种子层的形成和超级电镀钴填充7 nm微孔的技术工艺仍是一个很大的挑战。化学镀是在绝缘体表面形成金属种子层的一种非常简单的方法, 通过超级化学镀填充方式, 直径为几纳米的盲孔可以无空洞和无缝隙的方式完全填充。本文综述了化学镀钴的研究进展,并分析了还原剂种类对化学镀钴沉积速率和镀膜质量的影响。同时, 在长期从事超级化学填充研究的基础上, 作者提出了通过超级化学镀钴技术填充7 nm以及一下微盲孔的钴互连线工艺。     

高钐含量SmCo磁记录薄膜材料的研究

SmCo合金具有极高的单轴磁晶各向异性,成为未来高密度磁记录介质的候选材料之一.本文采用磁控溅射方法,在玻璃基片上制备了Cr(100nm)/SmCo(50 nm)/Cr(20 nm)结构的Smco薄膜,SmCo层中Sm含量为35%(原子分数).利用综合物性测试系统(PPMS)和X射线衍射(XRD)对薄膜的磁性能和晶体学结构进行了测试.结果表明,通过550℃退火20 min可以获得很好的硬磁性能,矫顽力R.达到了3183kA·m-1,XRD结果表明薄膜中同时存在磁性相SmCo5和非磁性相SmCo2等.高Sm古量的SmCo薄膜在退火温度为450℃时开始晶化,退火温度达到550℃时,晶化进行的比较完全.     

择优取向生长的Gd2O3高K栅介质薄膜

使用射频磁控溅射法在n型Si(001)基片上生长了Gd2O3薄膜。X射线衍射扫描研究和高分辨透射电子显微镜观察表明,薄膜由立方相和单斜相混合构成,且表现出立方(111)晶面和单斜(401)晶面的择优取向生长。XPS分析表明薄膜的元素组成接近化学计量比。电性能测试发现,薄膜拥有合适的介电常数,较小的漏电流密度和较大的击穿场强,厚度为15 nm的薄膜介电常数为23,漏电流密度为3.6×10-5A.cm-2(偏压为 1 V时),击穿场强为3.5 MV.cm-1。     

氯化钯掺杂的羧基丁苯胶乳薄膜的制备及用于化学镀铜性能

利用羧基丁苯胶乳优良的成膜性能,并通过氯化钯掺杂使薄膜具备催化化学镀的活性,在其表面进行化学镀铜研究,选用次亚磷酸钠和硼氢化钠为还原剂,将硫酸铜还原成单质铜。 采用扫描电子显微镜（SEM）、能量色散谱（EDS）和X射线衍射（XRD）等对其形貌、成分进行表征。 测试了胶膜的增重率、表面金属及沉积层的结合牢度。 结果表明,薄膜的表面形成均匀致密、导电性优良和结合力良好的铜层。 该方法可应用于平面非金属材料如聚酯透明材料、装饰板材等,获得了良好导电表面,形成具有电磁屏蔽功能的面型材,具有广阔应用前景。     

铜的彩色电镀

本文推荐一个中级无机化学实验。该实验是在我们多年探索的基础上,经精心编制而成。实验简单易行,可供理工科大学、师范院校化学系选用。通过本实验希望达到以下目的:(1) 熟悉铜的电化学特性;(2) 了解反应物浓度、外加电压对电解速度的影响;(3) 初步掌握装饰性电镀技术的基本原理。     

锂离子电池薄膜锡负极材料的制备及容量衰减机理研究

以电镀的方法在铜基底上沉积薄膜锡作为锂离子电池负极材料. 运用X射线衍射、扫描电镜、电化学循环伏安、电化学充放电和交流阻抗等多种方法对其结构和性能进行表征和研究. 结果表明所制备的薄膜锡电极主要为四方晶系结构, 其初始放电(嵌锂)容量为709 mAh•g^－1, 充电(脱锂)容量为561 mAh•g^－1. 电化学循环伏安研究发现在嵌/脱锂过程中薄膜锡经历了多种相变过程. 电化学阻抗谱结果说明, 首次嵌锂过程中当电极电位达到1.2 V在电极表面形成SEI膜, 而当电极电位低于0.4 V表面SEI膜出现破裂, 归因于体积膨胀所致. SEM研究表明30次充放电循环后薄膜锡负极出现龟裂现象.     

Effect of Heat Treatment on Structure and Magnetic Performance of Ni-Fe-P Alloy Obtained by Electroless Plating

The electroless deposition of Ni68-Fe10.5-P21.5 alloy has been investigated. The crystallization behavior of the deposit was comparatively studied by using differential scanning calorimetry and X-ray diffractometry. The deposit transforms into a square Ni3P phase at 380. 0 ℃, then changes into a cubic FeNi3 phase at 490. 0 ℃. The microhardness, the size of the formed grains and the magnetic performance of the deposit increase with the increase of the heat treatment temperature below 500 ℃, then they decrease after this temperature. The effect of heat treatment time at 500 ℃ on the surface micromorphology, the structure and the magnetic performance of the deposit were also studied. The resuits show that with the increase of heat treatment time, the extent of crystallization of the deposit increases and the size of the formed grains becomes uniform. The results also show that the magnetic performance of the deposit under heat treatment for 40 min is maximal and then decreases with the increase of heat treatment time. The property change of the deposit is related to the crystal structure and the size of the formed grains of the deposit.     

Electroless Nickel Plating and Electroplating on FBG Temperature Sensor

Metal-coated fiber Bragg grating（FBG）temperature sensors were prepared via electroless nickel（EN）plating and tin electroplating methods on the surface of normal bare FBG.The surface morphologies of the metal-coated layers were observed under a metallographic microscope.The effects of pretreatment sequence,pH value of EN plating solution and current density of electroplating on the performance of the metal-coated layers were analyzed.Meanwhile, the Bragg wavelength shift induced by temperature was monitored by an optical spectrum analyzer.Sensitivity of the metal-coated FBG（MFBG）sensor was almost two times that of normal bare FBG sensor.The measuring temperature of the MFBG sensor could be up to 280℃,which was much better than that of conventional FBG sensor.     

Hexagonal Ferrites from Melts and Aqueous Solutions,Magnetic Recording Materials

Owing to their particular crystallographic properties, ferrimagnetic hexagonal ferrites exhibit a far greater coercive force than the conventional magnetic pigments. They therefore appear to be suitable for use in magnetic information storage procedures, some of which are novel and are at the development stage. Thus, magnetic tapes of high coercive force containing barium ferrite could be used as master tapes for copying magnetic information or for producing forgery-proof magnetic cards, if magnetic heads having high-order write fields were successfully developed. Moreover, platelet-like ferrite pigments in which the preferred direction of magnetic orientation is perpendicular to the plane of the platelet are of great interest for perpendicular magnetic recording. In this progress report, the crystal structures, magnetic characteristics of hexagonal ferrites, and chemical processes for their production are discussed. In particular, reactions in salt melts or under hydrothermal conditions produce finely divided pigments whose particles have a pronounced hexagonal, plate-like habit, a narrow particle size distribution, and advantageous magnetic properties. The magnetic properties of the pigments crystallized from salt melts may be adjusted by cation exchange.     

镍钴磷包覆的碳纳米管与成分关联的磁性能

用化学镀方法在碳纳米管表面沉积了具有不同镍／钴成分配比的镍钴磷合金层．讨论了Co^2＋与Ni^2＋的浓度比、镀液温度、pH值对沉积速率的影响．并利用场发射扫描电镜、透射电镜、X射线衍射仪、能谱仪和磁性测疑仪对镍钴磷包覆碳纳米管进行了系统的结构和性能表征．结果表明：当镀液中Co^2＋与Ni^2＋的浓度比为1,pH值为9时沉积速率最大;镀液温度的升高会使沉积速率增大．磁性测试结果显示碳纳米管表面镀覆Ni—Co—P镀层后,其磁性能对镀层中的Ni、Co相对含量有强烈的依赖性．当Co^2＋：Ni^2＋=2：1时,饱和磁化强度最大．矫顽力分别在Co^2＋：Ni^2＋=1：2和Co^2＋：Ni^＋2＋=4：1时有2个峰值;而磁导率分别在Co^2＋：Ni^2＋=1：4和Co^2＋：Ni^2＋=4：1时有2个峰值．     

化学镀镍—高磷合金的微观结构及晶化行为研究

采用混合络合剂在酸性体系中进行化学镀镍－高磷合金,并用原子力显微镜（AFM）,透射电镜（TEM）、差热分析（DSC）、X射线衍射（XRD）等技术研究所得到的化学镀镍－高磷合金的微观结构和晶化行为。结果表明,化学镀镍－高磷合金具有胞状结构的微观形貌,镀态时呈典型的非晶态结构,300℃以下对热非常。镀层在343．8℃开始晶化,400℃时完全转化成亚稳用Ni5P2,440.4 ℃,时进一步转变成稳定的Ni和Ni3P相其晶化行为同从碱性乙二胺镀液中得到的高磷化学镀镍层有明显的差异。     

T-ZnO晶须化学镀铜复合粉体的制备及其电磁性能的研究

采用化学镀的方法制备了Cu包覆四脚状氧化锌晶须(T-ZnO晶须)的复合粉体.使用X射线衍射分析仪(XRD)进行了物象分析,扫描电镜(SEM)观察了粉体的形貌.运用能谱仪(EDS)进行了成份分析.结果表明,晶须为纯氧化锌,晶体结构为六方晶系纤锌矿结构,镀层为纯铜. SEM观察晶须外观形貌为四脚状结构.同时使用波导法对T-ZnO晶须和化学镀铜得到的Cu/T-ZnO晶须复合粉体进行了电磁参数的测量.微波电磁性能试验表明,化学镀后晶须的微波吸收性能明显增加,在频率为13 GHz处反射率可达－12 dB左右,而且最大吸收峰的频率随铜析出量的不同而发生改变,这样有利于实现吸收频带的展宽.     

Preparation and Magnetic Properties of Submicron CrO2 Thin Film on Poly-crystal TiO2 Film

The submicron chromium dioxide(CrO₂) thin film was fabricated on a poly-crystal titania(TiO₂) film using Si wafers as substrates by atmospheric pressure chemical vapor deposition(CVD) method. X-Ray diffraction patterns show that the CrO₂ films were pure rutile structure. Scanning electron microscopy(SEM) images indicate that the CrO₂ films consisted of submicron grains with a grain size of 250―750 nm. The magnetic researches reveal that the magnetic easy axis is parallel to the films, and at room temperature, the CrO₂ films show linear magnetoresistance.     

热辅助存储磁盘硅掺杂非晶碳薄膜氧化的ReaxFF反应力场分子动力学模拟

Heat-assisted magnetic recording (HAMR) is one of the promising ways to extend the magnetic recording area density to 1 Tb·in^-2 in hard disk drives (HDDs).High temperature induced by laser heating can cause carbon overcoat (COC) oxidation.Reactive molecular dynamics (MD) simulations are performed to investigate the oxidation process of silicon-doped amorphous carbon (a-C:Si) films for HAMR application.The atomic details of the structure evolution and oxidation process are investigated, and, the oxidation mechanism of the a-C:Si film is clarified.The effect of the duration of laser irradiation on the oxidation of the a-C:Si film is investigated.The oxidation occurs during heating and the beginning of cooling process.Both volume expansion during heating process and cluster of carbon atoms during cooling process increase the rate of sp² carbon.Because of the decrease in the amount of unsaturated silicon atoms and low diffusion coefficient of atomic oxygen, the oxidation rate of the a-C:Si film decreases with laser irradiation cycles.The molecular oxygen is the oxidant due to surface defect of a-C:Si film.The atomic strains break the O-O bonds in Si-O-O-Si linkages and rearrange the surface oxide layers, and process the oxidation of the a-C:Si film.     

酸性溶液化学镀Ni-P-B合金及结构性能表征(英文)

联用次亚磷酸钠和硼氢化钠两种还原剂 ,从酸性镀液中沉积出不同硼含量的Ni_P_B镀层 ,并用原子力显微镜、X_射线衍射、透射电镜、动电位扫描等实验技术对其镀态结构及性能进行了表征。实验表明 ,镀液中硼氢化钠含量对沉积速度影响不大 ,但能显著影响镀层的化学组成。硼的共沉积使镍晶格点阵产生扭变 ,导致镀层晶粒增大 ,表面粗糙 ,颗粒分布不均匀 ,并使镀层由非晶态向微晶结构转变 ,且微晶成分随镀层中硼含量的增加而增多。Ni_P_B镀层的硬度随镀层中硼含量的增加而增大 ,热处理能显著提高镀层的硬度 ,且服从沉淀硬化机理。在 3.5wt%NaCl和 40wt%NaOH两种介质中 ,Ni_P_B合金的耐腐蚀能力优于Ni_P合金。镀层中硼含量越高 ,其耐腐蚀能力越强。     

络合剂和添加剂对化学镀铜影响的电化学研究

以CuSO4·5H2O作主盐,乙二胺四乙酸二钠盐(Na2EDTA)作主络合剂,三乙醇胺(TEA)作辅助络合剂,2,2′＿联吡啶(dipyridine)作添加剂,组成化学镀铜液体系,研究络合剂、添加剂对该镀液电化学极化性能的影响,并结合化学沉积速率考察TEA和2,2′＿联吡啶对镀液性能的影响.