3G承载网发展向全业务时代挺进

在介绍面向全业务的3G需求及承载网现状的基础上,给出了干线/核心层IPoverWDM/OTN方案和汇聚/接入层综合解决方案,最后介绍了面向未来的3G承载网。     

C8 BTBT薄膜结晶形貌及OTFT器件性能研究

以p型共轭有机小分子2,7二辛基[1]苯并噻吩并[3,2‐b]苯并噻吩(C8‐BTBT)作为底栅顶接触有机薄膜晶体管(OTFT)的有源层,采用浸渍提拉法、喷墨打印法和真空蒸镀法三种制备工艺,探究半导体薄膜载流子迁移率与结晶形貌的关系,发现不同工艺下有机小分子呈现出不同的生长行为和结晶情况,在很大程度上决定了OTFT器件性能的优劣;此外,通过XRD分析研究了退火处理对C8‐BTBT结晶的影响。结果表明,真空蒸镀制备的薄膜具有更高的结晶度、衬底覆盖率高,并且呈现出SK(Stranski‐Krastanov)模式的结晶生长特征,相应器件中陷阱密度最低,迁移率高达5.44 cm^2·V^-1·s^-1,开关比超过106;且退火处理会严重破坏C8‐BTBT薄膜的结晶。因此,控制半导体层的生长行为,提升半导体层的覆盖率和结晶度是制备高性能共轭小分子OTFT器件的有效途径。     

对扫描电镜观察微生物样品出现磷酸盐结晶现象的改良

制备常规扫描电镜生物样品时,通常使用磷酸缓冲液来进行漂洗,其结果是容易产生结晶,沉积在样品表面.针对微生物具有坚韧的细胞壁的特性,作者使用去离子水替代磷酸缓冲液来漂洗固定液.结果显示,扫描电镜下样品形态完好,无磷酸盐结晶,提高了样品制备的成功率.     

Impact of Processing on Structural and Compositional Evolution in Mixed Metal Halide Perovskites during Film Formation

Understanding crystallization processes and their pathways in metal‐halide perovskites is of crucial importance as this strongly affects the film microstructure, its stability, and device performance. While many approaches are developed to control perovskite formation, the mechanisms of film formation are still poorly known. Using time‐resolved in situ grazing incidence wide‐angle X‐ray scattering, the film formation of perovskites is investigated with average stoichiometry Cs_0.15FA_0.85PbI₃, where FA is formamidinium, using the popular antisolvent dropping and gas jet treatments and this is contrasted with untreated films. i) The crystallization pathways during spin coating, ii) the subsequent postdeposition thermal annealing, and iii) crystallization during blade coating are studied. The findings reveal that the formation of a nonperovskite FAPbI₃ phase during spin coating is initially dominant regardless of the processing and that the processing treatment (e.g., antisolvent dropping, gas jet) has a significant impact on the as‐cast film structure and affects the phase evolution during subsequent thermal treatment. It is shown that blade coating can be used to overcome the nonperovskite phase formation via solvothermal direct crystallization of perovskite phase. This work shows how real‐time investigation of perovskite formation can help to establish processing–microstructure–functionality relationships.     

叠层芯片应用的封装挑战与解决方法

叠层管芯封装的不断发展导致该技术能有效地在同一基底内增大电子器件的功能和容量,作为单个芯片。蜂窝电话及其它消费类产品中叠层芯片封装的应用增长促使能够在给定封装尺寸中封装多层芯片。介绍了叠层芯片封装技术中最主要是满足总封装高度的要求。用于叠层芯片封装的技术实现方法包括基片减薄、薄裸芯片贴装、小形貌引线键合、与无支撑的边缘键合以及小偏倒成形等。集中介绍了叠层管芯互连要求。介绍了倒装芯片应用中的正向球形键合、反向球形键合和焊凸凸焊技术,讨论了优点和不足。说明球形键合机的发展能够满足叠层芯片封装的挑战,即超低环形状、长引线跨距和悬空键合等。     

Solution processable bilayered gate dielectric towards flexible organic thin film transistors

In this study, we have successfully explored the potential of a new bilayer gate dielectric material, composed of Polystyrene (PS), Pluronic P123 Block Copolymer Surfactant (P123) composite thin film and Polyacrylonitrile (PAN) through fabrication of metal insulator metal (MIM) capacitor devices and organic thin film transistors (OTFTs). The conditions for fabrication of PAN and PS-P123 as a bilayer dielectric material are optimized before employing it further as a gate dielectric in OTFTs. Simple solution processable techniques are applied to deposit PAN and PS-P123 as a bilayer dielectric layer on Polyimide (PI) substrates. Contact angle study is further performed to explore the surface property of this bilayer polymer gate dielectric material. This new bilayer dielectric having a k value of 3.7 intermediate to that of PS-P123 composite thin film dielectric (k ∼ 2.8) and PAN dielectric (k ∼ 5.5) has successfully acted as a buffer layer by preventing the direct contact between the organic semiconducting layer and high k PAN dielectric. The OTFT devices based on α,ω-dihexylquaterthiophene (DH4T) incorporated with this bilayer dielectric, has demonstrated a hole mobility of 1.37 × 10⁻² and on/off current ratio of 10³ which is one of the good values as reported before. Several bending conditions are applied, to explore the charge carrier hopping mechanism involved in deterioration of electrical properties of these OTFTs. Additionally, the electrical performance of OTFTs, which are exposed to open atmosphere for five days, can be interestingly recovered by means of re-baking them respectively at 90 °C.     

Crystallization kinetics of Sn40Se60 thin films for phase change memory applications

The crystallization kinetics of Sn₄₀Se₆₀ thin films has been successfully investigated using sheet resistance versus temperature measurements. Thermal evaporation was used to deposit the films on ordinary glass substrates. The crystallization temperature for Sn₄₀Se₆₀ thin film was found to be 156.6 ± 0.3 ℃. In the as-deposited state, the sheet resistance was found to be 195 MΩ, this value declined to 1560 Ω/口 upon annealing. The value of activation energy obtained from the Kissinger plot was 0.62 ± 0.07 eV. From the results obtained, Sn₄₀Se₆₀ is a promising alloy for PCM application because of its high electrical contrast, high crystallization temperature, and relatively high activation energy.     

Influence of oxygen content on the crystallinity of MgO layers in magnetic tunnel junctions

With RF sputtering process, Si/Si02/Ta/Ru/Ta/CoFeB/MgO/CoFeB/Ta/Ru structure has been grown on Si （100） substrate. Attempting different targets and adjusting the oxygen dose, the crystallization quality of the MgO layer is studied. The X-ray diffraction measurements demonstrate that crystal structure and crystallization quality of MgO layers are related to the type of target and concentration of oxygen in sputtering process. With the method sputtering Mg in an ambient flow of oxygen, not only the crystallization quality of a normal MgO layer with lattice constant of 0.421 nm is improved, but also a new MgO crystal with lattice constant of 0.812 nm is formed and the perpendicular magnetic anisotropy of CoFeB is enhanced. Also it is found that crystallization quality for both the normal MgO and new MgO is more improved with MgO target and same oxygen dose, which means that this new method is helpful to form a new structure of MgO annealed at 400 ℃ in vacuum. with lattice constant of 0.812 nm. All of the samples were