SiC MESFET工艺技术研究与器件研制

针对SiC衬底缺陷密度相对较高的问题,研究了消除或减弱其影响的工艺技术并进行了器件研制.通过优化刻蚀条件获得了粗糙度为2.07 nm的刻蚀表面;牺牲氧化技术去除刻蚀带来的表面损伤层,湿氧加干氧的氧化方式生长的SiO2钝化膜既有足够的厚度又保证了致密性良好的界面,减小了表面态对栅特性和沟道区的影响,获得了理想因子为1.17,势垒高度为0.72 eV的良好的肖特基特性;等平面工艺有效屏蔽了衬底缺陷对电极互连引线的影响,减小了反向截止漏电流,使器件在1 mA下击穿电压达到了65 V,40 V下反向漏电流为20μA.为了提高器件成品率,避免或减小衬底缺陷深能级对沟道电流的影响,使用该工艺制备的小栅宽SiCMESFET具有195 mA/mm的饱和电流密度,-15 V的夹断电压.初步测试该器件有一定的微波特性,2 GHz下测试其最大输出功率为30 dBm,增益大于5 dB.     

Transport mechanism of reverse surface leakage current in AlGaN/GaN high-electron mobility transistor with SiN passivation

The transport mechanism of reverse surface leakage current in the AlGaN/GaN high-electron mobility transistor(HEMT) becomes one of the most important reliability issues with the downscaling of feature size.In this paper,the research results show that the reverse surface leakage current in AlGaN/GaN HEMT with SiN passivation increases with the enhancement of temperature in the range from 298 K to 423 K.Three possible transport mechanisms are proposed and examined to explain the generation of reverse surface leakage current.By comparing the experimental data with the numerical transport models,it is found that neither Fowler-Nordheim tunneling nor Frenkel-Poole emission can describe the transport of reverse surface leakage current.However,good agreement is found between the experimental data and the two-dimensional variable range hopping(2D-VRH) model.Therefore,it is concluded that the reverse surface leakage current is dominated by the electron hopping through the surface states at the barrier layer.Moreover,the activation energy of surface leakage current is extracted,which is around 0.083 eV.Finally,the SiN passivated HEMT with a high Al composition and a thin AlGaN barrier layer is also studied.It is observed that 2D-VRH still dominates the reverse surface leakage current and the activation energy is around 0.10 eV,which demonstrates that the alteration of the AlGaN barrier layer does not affect the transport mechanism of reverse surface leakage current in this paper.     

Weierstrass-Mandelbrot函数的非单调类性

非单调类性质在连续函数研究中起着重要作用．众所周知，Weierstrass函数具有非单调类性质．本文证明了Weierstrass-Mandelbrot型函数具有非单调类性质．     

消失广义加权Morrey空间上的分数次积分算子(英文)

本文主要研究了带粗糙核的分数次积分算子及其与BMO函数生成的交换子在消失广义加权Morrey空间上的有界性.     

用VBA扩展Microsoft Office 2000功能

通过一个实例介绍利用VBA扩展Office 2000内置功能的方法。     

铁(Ⅲ)-硫氰酸钾-结晶紫光度法测定高纯稀土中痕量铁

在 0 .0 3— 0 .0 6 mol/L的硫酸溶液中 ,在阿拉伯树胶存在下 ,铁与硫氰酸钾、结晶紫生成可溶性离子缔合物 ,该缔合物表观摩尔吸光系数为 4 .78× 10 5L· mol-1· cm-1,经甲基异丁基酮 (MIBK)萃取分离 ,铁的浓度在 0— 2 .5μg/m L范围内符合比耳定律。此方法用于高纯稀土中痕量铁的测定 ,结果令人满意     

投影未来携手共赢Vivitek丽讯2013年网庭全国渠道会议暨新品发表会

北京时间2013年7月1日上午10点,Vivitek丽讯携手家用投影机中国总代理商网庭影音机构(以下简称网庭),在江苏吴江生产基地,隆重召开2013年丽讯及网庭全国渠道会议暨新品发表会. Vivitek丽讯家用投影机新品发表会会议现场. Vivitek丽讯中国区CEO林中庸先生代表丽讯中国向参加本次会议的渠道伙伴和媒体朋友表示热烈的欢迎,林先生在发言中谈到,一直以来,丽讯通过坚持不懈的技术革新与进步,持续完善家用投影机产品,将会陆续推出更多符合国内家用投影市场需求的新品.     

三菱全高清3D投影机——继续让利消费者

三菱多年来一直是许多家用投影机爱好者首选的品牌,三菱为了能够不断满足家庭影院消费者对高画质多层次的需要,都会定期针对家用市场带来新款产品。而针对当下3D显示技术的火热,三菱也是有备而来。凭借在投影领域领先业界的技术,三菱接连推出两款全高清3D家用投影机HC77—80D和HC77—70D。     

Hierarchical structure and biomineralization in cricket teeth

The cricket is a truculent insect with stiff and sharp teeth as a fighting weapon. The structure and possible biomineralization of cricket teeth are always interesting. Synchrotron radiation X-ray fluorescence, X-ray diffraction, and small angle X-ray scattering techniques were used to probe the element distribution, possible crystalline structures and size distribution of scatterers in cricket teeth. A scanning electron microscope was used to observe the nanoscaled structure. The results demonstrate that Zn is the main heavy element in cricket teeth. The surface of a cricket tooth has a crystalline compound like ZnFe2(AsO4)2(OH)2(H2O)4 . The interior of the tooth has a crystalline compound like ZnCl2 , which is from the biomineralization. The ZnCl2-like biomineral forms nanoscaled microfibrils and their axial direction points towards the top of the tooth cusp. The microfibrils aggregate randomly into intermediate filaments, forming a hierarchical structure. A sketch map of the cricket tooth cusp is proposed and a detailed discussion is given in this paper.     

重炮出击家用市场——爱普生两款新品演绎巅峰境界

11月28日,基于对家用投影市场潜力与需求的良好预见与判断,爱普生公司推出了面向发烧友及中高端用户的两款1080P新品,其中EH—TW4500作为EH—TW4000的升级产品,对比度高选200000：1,成为傲祝市场的新科“对比度之王”,如此高规格参数的顶级精品也生动体现了爱普生公司作为领导品牌的技术研发实力与市场推动力。