UHVCVD外延设备的热场设计

介绍了超高真空化学气相沉积(UHVCVD)锗硅外延设备的加热室设计方法,完善了相关的炉体设计,相关温度指标达到设计标准。     

纳米级三氧化二铝对碱性钨抛光液的影响

研究了纳米级三氧化二铝颗粒的加入对以二氧化硅为磨料的碱性钨抛光液的影响。首先用单一因素法分析了三氧化二铝与二氧化硅质量比对原有碱性钨抛光液的去除速率的影响,以及氧化剂体积分数和pH值对抛光液去除速率的影响,取最优值,然后对添加三氧化二铝抛光液抛光后晶圆表面粗糙度进行了测试分析。实验结果显示在三氧化二铝与二氧化硅质量比为1∶2,二氧化硅水溶胶与去离子水体积比为1∶1,氧化剂体积分数为2%,pH值为9时,去除速率达到175 nm/min,较原有碱性钨抛光液提高约1倍,表面粗糙度为2.24 nm,能满足实际生产要求。     

聚噻吩类有机聚合物材料光电性能研究进展

介绍了典型的具有光电性能的噻吩类聚合物材料,包括烷基取代聚噻吩、联苯基取代聚噻吩、芴与噻吩共聚物及一些新型的噻吩类聚合物。对它们的结构、光学性能、电致发光性能进行了归纳和总结,讨论了不同类聚噻吩的特点,对比了随取代基种类、位置及个数的不同其聚合物性能的优缺点,并对其研究和应用前景进行了展望。     

锥形图形衬底上氮化镓薄膜生长和表征

GaN films are grown on cone-shaped patterned sapphire substrates(CPSSs)by metal-organic chemical vapor deposition,and the influence of the temperature during the middle stage of GaN growth on the threading dislocation(TD)density of GaN is investigated.High-resolution X-ray diffraction(XRD)and cathodeluminescence(CL)wereusedtocharacterizetheGaNfilms.TheXRDresultsshowedthattheedge-typedislocation density of GaN grown on CPSS is remarkably reduced compared to that of GaN grown on conventional sapphire substrates(CSSs).Furthermore,whenthegrowthtemperatureinthemiddlestageofGaNgrownonCPSSdecreases,the full width at half maximum of the asymmetry(102)plane of GaN is reduced.This reduction is attributed to the enhancement of vertical growth in the middle stage with a more triangular-like shape and the bending of TDs.The CL intensity spatial mapping results also showed the superior optical properties of GaN grown on CPSS to those of GaN on CSS,and that the density of dark spots of GaN grown on CPSS induced by nonradiative recombination is reduced when the growth temperature in the middle stage decreases.     

煅烧温度和恒温时间对ZnO/AAO/Si组装体系的影响

以AAO/Si为模板,采用化学气相沉积(CVD)的方法在不同温度下,通过煅烧Zn粉和C粉的混合物制备ZnO/AAO/Si组装体系,并对其结构和性质进行了研究。扫描电镜(SEM)结果表明:随着煅烧温度的升高,AAO表面的孔洞逐渐被封堵,当温度达到900℃时,在AAO的表面出现了一层ZnO薄膜。X射线衍射(XRD)结果显示,700℃时在XRD图谱上观看到六角纤锌矿的ZnO的衍射峰,并且随着温度的升高,ZnO的衍射峰逐渐增强,当温度升至800和900℃时出现了ZnAl2O4的衍射峰。因此,化学气相沉积制备组装体系时的最适温为700℃。在700℃时煅烧不同恒温时间制备的ZnO/AAO/Si组装体系SEM图显示,随着恒温时间的延长,孔的封闭效应逐渐明显。     

Protein Engineering Strategies for Improved Pharmacokinetics

Protein therapeutics have gained momentum in recent years and become a pillar in treating many diseases and the only choice in several ailments. Protein therapeutics are highly specific, tunable, and less toxic than conventional small drug molecules. However, reaping the full benefits of therapeutic proteins in the clinics is often hindered by issues of immunogenicity and short half-life due essentially to fast renal clearance and enzymatic degradation. Advances in polymer chemistry and protein engineering allowed overcoming some of these limitations. Strategies to prolong the half-life of proteins rely on increasing their size and stability and/or fusing them to endogenous proteins (albumin, Fc fragment of antibody) to hijack physiological pathways involved in protein recycling. On the downside, these modifications might alter therapeutic proteins structure and function. Therefore, a compromise between half-life and activity is sought. This review covers half-life extension strategies using natural and synthetic polymers as well as fusion to other proteins and sheds light on genetic engineering strategies and chemical and enzymatic reactions to achieve this goal. Promising strategies and successful applications in the clinics are highlighted.     

1.06μm大功率连续半导体激光器

利用金属有机化学气相淀积(MOCVD)技术,生长了InGaAs/AlGaAs分别限制压应变双量子阱和单量子阱两种材料结构,通过对不同腔长单管激光器的LIV测试获得内部参数,对单、双阱两种材料结构器件参数进行对比分析,确定了单量子阱结构作为1.06μm大功率半导体激光器的材料结构。通过研究单管激光器的电光转换效率与腔长、注入电流的关系,获得了最高达到57.5%的电光转换效率。对1mm腔长单管激光器进行了大电流高温加速老化测试,结果显示研制出的单管激光器室温下在1.5A工作电流下寿命远大于104h。     

CMP承载器的初步研究

在CMP中,由于抛光垫在与其接触的晶圆边缘产生异常压力点,以及转台和承载器旋转的线速度之差在边缘处较其他点大得多,从而导致了晶圆边缘效应的产生。阐述了承载器在CMP中的作用,详细分析了边缘效应产生的原因和克服的方法。在承载器上采用与晶圆保持适当间隙的保持环结构,对保持环施加适当的压力,使保持环和晶圆位于同一抛光平面上;针对旋转式CMP设备固有的线速度之差导致片内非均匀性增大的问题,对200mm晶圆划分两区域进行微压力补偿,同时详细说明了压力补偿气路的设计和实现的功能,指出今后多区域微压力补偿将采用矩阵控制技术。     

High power λ～8.5 μm quantum cascade laser grown by MOCVD operating continuous-wave up to 408 K

Robust quantum cascade laser(QCL)enduring high temperature continuous-wave(CW)operation is of critical import-ance for some applications.We report on the realization of lattice-matched InGaAs/lnAIAs/InP QCL materials grown by metal-organic chemical vapor deposition(MOCVD).High interface quality structures designed for light emission at 8.5μmare achieved by optimizing and precise controlling of growth conditions.A CW output power of 1.04 W at 288 K was obtained from a 4 mm-long and 10 μm-wide coated laser.Corresponding maximum wall-plug efficiency and threshold current density were 7.1％and 1.18 kA/cm2,respectively.The device can operate in CW mode up to 408 K with an output power of 160 mW.     

受激布里渊散射(SBS)中的三类介质

介绍了目前使用的三类受激布里渊散射介质的化学结构及其SBS性能．并且分析了受激布里渊散射对介质的要求，