基于二维扩散方程的牺牲层腐蚀模拟与仿真

深入研究了牺牲层腐蚀机制,给出了可以在二维平面中模拟腐蚀过程的仿真程序。由于腐蚀主要由腐蚀溶液的扩散机制所影响,对溶液的二维扩散方程给出了求解的有限差分算法,得到了在具体时间和位置的浓度,再利用T opography模型计算腐蚀前端面的腐蚀进行情况得到腐蚀前端行进的轮廓线,通过编程得到了能够模拟不同开口牺牲层结构的仿真程序。最后给出模拟结果和实验腐蚀结果的对比。     

非制冷焦平面探测器牺牲层制备工艺研究

研究了牺牲层制备的工艺过程。通过对牺牲层材料选择、牺牲层图形化及牺牲层固化等工艺技术的研究,获得了图形质量较好的牺牲层样品。建立了优化的牺牲层制备工艺制度,为探测器的后续研究奠定了基础。     

RF MEMS开关工艺技术研究

RFMEMS开关是用MEMS技术形成的新型电路元件,与传统的半导体开关器件相比具有插入损耗低、隔离度大等优点,将对现有雷达和通信中RF结构产生重大影响。文章介绍了RFMEMS开关的基本工艺流程设计,工艺制作技术的研究。实验解决了种子层技术、聚酰亚胺牺牲层技术、微电镀技术的工艺难题,制作出了RFMEMS开关样品,基本掌握了RFMEMS器件的制作工艺技术。RFMEMS开关样品测试的技术指标为:膜桥高度2μm～3μm、驱动电压<30V、频率范围0～40GHz、插入损耗≤1dB、隔离度≥20dB,样品参数性能达到了设计要求。     

Simplified Electrochemically Mediated Atom Transfer Radical Polymerization using a Sacrificial Anode

Simplification of electrochemically mediated atom transfer radical polymerization was achieved efficiently under either potentiostatic or galvanostatic conditions using an aluminum wire sacrificial anode (seATRP) immersed directly into the reaction flask without separating the counter electrode. seATRP polymerizations were carried out under different applied potentials, E_apps=E_1/2, E_pc, E_pc ?40 mV, and E_pc ?80 mV. As the rate of polymerization (R_p) can be modulated by applying different E_app potentials, more reducing conditions resulted in faster R_p. The polymerization results showed similar narrow molecular‐weight distribution throughout the reactions, similar to results observed for n‐butyl acrylate (BA) polymerization under conventional eATRP. High‐molecular‐weight PBA and diblock copolymers were synthesized by seATRP with more than 90 % monomer conversion. Furthermore, galvanostatic conditions were developed for synthesizing PBA with the two‐electrode system.     

Bioinspired Interface Engineering in Elastomer/Graphene Composites by Constructing Sacrificial Metal–Ligand Bonds

It remains a huge challenge to create advanced elastomers combining high strength and great toughness. Despite enhanced strength and stiffness, elastomeric nanocomposites suffer notably reduced extensibility and toughness. Here, inspired by the concept of sacrificial bonding associated with many natural materials, a novel interface strategy is proposed to fabricate elastomer/graphene nanocomposites by constructing a strong yet sacrificial interface. This interface is composed of pyridine‐Zn²⁺‐catechol coordination motifs, which is strong enough to ensure uniform graphene dispersion and efficient stress transfer from matrix to fillers. Moreover, they are sacrificial under external stress, which dissipates much energy and facilitates chain orientation. As a result, the strength, modulus, and toughness of the elastomeric composites are simultaneously strikingly enhanced relative to elastomeric bulk. This work suggests a promising methodology of designing advanced elastomers with exceptional mechanical properties by engineering sacrificial bonds into the interface.

     

射频微机械CPW开关的研究

本文采用聚酰亚胺牺牲层技术和二氧化硅介质隔离技术,成功地在绝缘多晶硅衬底上研制出一种射频微机械CPW开关.初步测试结果如下:开态电容为0.21pF,关态电容为6.1pF,致动电压为22V,关态下的隔离度为35dB,开态下插入损耗为3dB.该工艺完全与硅基IC工艺兼容,这为射频微机械CPW开关与IC实现单片集成化,降低体积提高可靠性打下了基础.     

用于MEMS的选择性形成多孔硅技术的研究

提出了一套采用扩散工艺在低掺杂的硅衬底上选择性形成多孔硅牺牲层,并制作了MEMS器件结构的工艺流程,进行了工艺流水.对得到的结果进行了详细的讨论.对于KOH溶液释放多孔硅牺牲层技术进行了研究.     

多晶硅微机械开关

利用LPCVD SiO2和多晶硅作牺牲层和悬臂梁技术,解决了多晶硅应力释放问题以及微机械开关工艺与IC工艺兼容技术问题,获得了淀积弱张应力的多晶硅膜的最佳工艺条件,研制出多晶硅微机械开关.初步测试出其开关的开启电压为89V,开关速度为5μs,这为研制用于雷达和通讯的全单片集成的RF MEMS开关系统打下了基础.     

Macroporous SiC?MoSi2 ceramics from templated hybrid MoCl5–polymethylsilane

A molybdenum‐containing preceramic polymer, MoPMS, was synthesized for the first time by HCl elimination of polymethylsilane (PMS) and MoCl₅ at room temperature in tetrahydrofuran. The insoluble MoPMS prepared was embedded into the void spaces of a silica colloidal crystal template within the pot life of the polymer and successfully transformed to a three‐dimensionally long‐range‐ordered macroporous SiC? MoSi₂ ceramic after pyrolysis at 1400 °C in an argon atmosphere followed by template removal in HF. The bead‐inverse macroporous SiC? MoSi₂ ceramic, with a ceramic yield of about 88%, exhibits high temperature stability, high BET surface area, and semiconducting behavior. In addition, the macroporous SiC? MoSi₂ ceramic was used as a catalyst carrier for platinum–ruthenium coated on the surface of the pores. The preceramic polymer and the ceramic were characterized by IR, thermogravimetric analysis, X‐ray diffraction, scanning and transmission electron microscopy, and BET surface area. Copyright © 2005 John Wiley & Sons, Ltd.