用于40Gb/s光电子器件的新型低成本硅基过渡热沉

提出了一种新型低成本硅基过渡热沉,用以实现高达40Gb/s的高速光电子器件封装.采用高阻硅衬底作为热沉基底,制作出了0～40GHz范围内传输损耗小于0.165dB/mm的共面波导传输线.热沉中采用Ta2N薄膜电阻作为负载以实现器件的阻抗匹配,达到了0～40GHz范围内低于-18dB的宽带低反射特性.和传统硅基平台相比,新型硅基热沉更具有制作工艺简单、导热性能良好等优点.为了证明其实用性,热沉被应用于高速电吸收调制器的管芯级封装测试,获得了超过33GHz的小信号调制带宽特性,在硅基热沉上首次实现可用于40Gb/s系统的光电子器件.

贵州省沉积型铝土矿“移硅沉铁富铝”成矿模式探讨

通过对贵州铝土矿的成矿地质背景、成因机制及前人的模拟实验等综合研究,认为广西运动末期使贵州地壳隆升和湿热的低纬度环境,地表岩石接受广泛的风化剥蚀,残留了以铝硅铁氧化物为主的红土化风化壳。经流水搬运集中于富含古生物的黔中—黔东—黔北地区泻湖盆(湾)中弱酸—还原性沉积环境,进行了重要“移硅沉铁富铝”的元素迁移与富集;而晚古生代早中期背景下的地壳稳定,形成了厚层—巨厚层富铝连续沉积层,造就了贵州4个重要的大中型—超大型矿集区,成为我国重要的铝资源大省;主要赋矿地层为下石炭统九架炉组—中下二叠统大竹园组、梁山组,形成了早石炭—早中二叠世是贵州铝土矿形成的特定时期。因此,晚古生代中晚期地层中可能存在隐伏的铝土矿,还可能存在新的大型一超大型矿集区,在全国范围内更可能存在相似条件下的大规模铝土矿。

锗富集物中硫、砷及二氧化硅的控制

针对高硫、砷二氧化硅等劣质原料中提取锗的过程中出现的质量问题 ,进行了除硫、砷及硅的研究。结果表明 ,采用高温除硫、氧化除砷及二段除硅效果显著 ,从而确保了锗富集物的质量达标。

锗富集物中硫、砷及二氧化硅的控制

对高硫、砷、二氧化硅等劣质原料提取锗进行了除硫、砷及硅的研究。结果表明 ,采用高温除硫、氧化除砷及二段除硅效果显著。

锗富集物中硫、砷及二氧化硅的控制

针对从高硫、砷、二氧化硅等劣质原料中提取锗的过程中出现的质量问题，进行了除硫、砷及硅的研究。结果表明，采用高温除硫、氧化除砷及二段除硅效果显著。从而确保了锗富集物的质量达标。

黑液铝沉木质素@PAN基碳纤维电极材料电化学性能及其超级电容器应用研究

采用硫酸铝胶体沉淀分离竹浆黑液高分子质量木质素,得到铝沉木质素(AlpL),以AlpL和聚丙烯腈(PAN)为原料,采用静电纺丝法-预氧化-碳化路线,制备了电化学性能良好的AlpL@PAN基碳纤维并研究其作为超级电容器电极材料的电化学性能。当AlpL占比为60%时,AlpL@PAN基碳纤维表现出最好的电容性能和较好的循环稳定性;其内部电阻值达1.138Ω,循环1000次后仍能保留94.50%的电容。

黄磷电尘灰中镓的加压酸浸试验

对黄磷电尘灰中的镓进行了加压硫酸浸出研究,重点考察了硫酸质量浓度、液固比、反应温度、浸出时间对浸出效果的影响。结果表明在较优工艺条件下,镓的浸出率为97.14%,SiO_2截留率为97.75%,氟的浸出率仅为2.73%,实现了镓的选择性浸出和酸浸液沉硅脱氟的综合效果,浸出矿浆过滤性能良好。镓的提取效果与硅胶的形成情况密切相关,高温条件有利于酸浸液中可溶性硅转化成晶态SiO_2及维持高的镓浸出率。

Influence of sodium silicate on manganese electrodeposition in sulfate solution

The influences of sodium silicate on manganese electrodeposition in sulfate solution were investigated. Manganese electrodeposition experiments indicate that a certain amount of sodium silicate can improve cathode current efficiency and initial pH 7.0?8.0 is the optimized pH for high cathode current efficiency. The analyses of scanning electron microscopy (SEM) and X-ray diffraction (XRD) indicate the compact morphology and nanocrystalline structure of electrodeposits. X-ray photoelectron spectrometry (XPS) analysis shows that the elements of Mn, Si and O exist in the deposit. The solution chemistry calculations of sulfate electrolyte and sodium silicate solution indicate that species of Mn2+, MnSO4, Mn(SO4)2?2 , Mn2+, MnSiO3, Mn(NH3)2+, SiO32?and HSiO3? are the main active species during the process of manganese electrodeposition. The reaction trend between Mn2+ and Si-containing ions is confirmed by the thermodynamic analysis. In addition, polarization curve tests confirm that sodium silicate can increase the overpotential of hydrogen evolution reaction, and then indirectly improve the cathode current efficiency.

Distribution of Biogenic Silica Content in Surface Sediments from the Southern South China Sea and Its Environmental Dignificance

Biogenic silica content was determined in 25 surface sediment samples from the southern South China Sea to study its distribution and its modern oceanic environmental significance, which may provide further scientific evidence for paleoceanography explaination. This study showed that biogenic silica content in surface sediments and its water depth have evidently positive correlation, and the correlation coefficient was up to 0.782. Biogenic silica content was very low in continental shelf shallows and could not reflect the productivity of siliceous micropaleontology in surface waters, which may be affected by sedimentary types and terrigenous matter dilution. Distribution of biogenic silica content in surface sediments from deep water areas showed that it could not only reflect the paleoproductivity of siliceous micropaleontology in surface waters, but also indicate the strong or feeble upwelling. Thus, it was further confirmed that using biogenic silica content in sediments to trace upwelling and its change was effective and reliable. The analyzed result showed that radiolariia and poriferous specula have more contribution for biogenic opal, comparing with diatom in surface sediments from the northern studied area, probably owing to the diatom dissolved easily away and eaten by other organisms with little effort. In the upwelling areas, radiolarian, diatom and poriferous specula all approximately showed high abundance, which was consistent with high biogenic silica content.

Impact of Transition-Metal Contamination on Oxygen Precipitation in Czochralski Silicon Under Rapid Thermal Processing

The effects of the transition metals copper and nickel on oxygen precipitation in Czochralski silicon under a rapid thermal process are investigated. It is found that interstitial copper has almost no effect on oxygen precipitation,but copper precipitation markedly enhances oxygen precipitation. However, neither interstitial nickel nor nickel precipitation affects oxygen precipitation. The reasons for the effects of copper and nickel contamination on oxygen precipitation are discussed in light of oxygen precipitation nucleation theory.

Improved Epitaxy of 3C-SiC Layers on Si(100) by New CVD/LPCVD System

Single crystalline 3C-SiC epitaxial layers are grown on φ 50mm Si wafers by a new resistively heated CVD/LPCVD system,using SiH_4,C_2H_4 and H_2 as gas precursors.X-ray diffraction and Raman scattering measurements are used to investigate the crystallinity of the grown films.Electrical properties of the epitaxial 3C-SiC layers with thickness of 1～3μm are measured by Van der Pauw method.The improved Hall mobility reaches the highest value of 470cm 2/(V·s) at the carrier concentration of 7.7×10 17 cm -3 .

Doped-Chamber Deposition of Intrinsic Microcrystalline Silicon Thin Films and Its Application in Solar Cells

A series of microcrystalline silicon thin films were fabricated by very high frequency plasma enhanced chemical vapor deposition （VHF-PECVD） at different silane concentrations in a P chamber. Through analysis of the structural and electrical properties of these materials,we conclude that the photosensitivity slightly decreased then increased as the silane concentration increased,while the crystalline volume fraction indicates the opposite change. Results of XRD indicate that thin films have a （220） preferable orientation under certain conditions. Microcrystalline silicon solar cells with conversion efficiency 4. 7% and micromorph tandem solar cells 8.5% were fabricated by VHF-PECVD （p layer and i layer of microcrystalline silicon solar cells were deposited in P chamber）, respectively.

Development of Sedimentary Environment in the Northeastern South China Sea Since the Last Glacial Stage

Core D （21°23′02″N, 116°47′13″E, water depth 405 m） was sampled from the upper slope from the northeastern South China Sea （SCS） and applied to analyze the sedimentary environmental change in this sea area since the last glacial stage. The results of grain size analysis, diatom analysis and detrital mineral analysis were well matched. We divided the core D into two layers. The surface sand layer （0 - 2 cm） consisted of residual sediments, which might be originally the sediment in the late Pleistocene and later suffered from being transformed in the post glacial transgression. The lower layer （2 - 130 cm） was quite different from the surface one, which might mainly result from a neritic sedimentary environment in the last glacial stage. Two sedimentary cycles could be detected in the core D： regression during Marine isotope stage （MIS） 4 to transgression during MIS 3 and regression during MIS 2 to transgression during the post glacial.

Recovery of high purity silicon from SoG crystalline silicon cutting slurry waste

The composition and size distribution of cutting waste were characterized. The Si-rich powders were obtained from the cutting waste using a physical sedimentation process, and then further purified by removing impurity using acid leaching. The effects of process parameters such as acid leaching time, temperature and the ratio of solid to liquid on the purification efficiency were investigated, and the parameters were optimized. Afterwards, the high-purity Si ingot was obtained by melting the Si-rich powders in vacuum furnace. Finally, the high purity Si with 99.96%Si, 1.1×10^-6 boron （B）, and 4.0×10^-6 phosphorus （P） were obtained. The results indicate that it is feasible to extract high-purity Si, and further produce SoG-Si from the cutting slurry waste.

贵州省铝土矿矿床特征分析

铝是地壳上最丰富的元素之一,要形成矿床必须有独特的地质背景和成矿条件,加里东晚期-海西早期运动产生裂陷背景下的大陆裂谷盆地,造就了黔中泻湖海盆、凯里海湾和渝南-黔北半封闭泻湖海湾的湿热古地理环境。使早古生代-晚古生代早期各类岩石接受风化剥蚀,达到前期的"排杂"使铝得到初步富集,搬运到泻湖海盆沉积和后期的"降硅沉铁"作用"脱颖而出"并沉积形成铝土矿矿床。中新生代的印支燕山-喜山运动造就的挤压背景-隆升背景,产生的前陆盆地-山间盆地,改变了成矿条件,不再形成铝土矿。铝土矿属沉积型矿床产于特定地层中,在省内有可能存在新的隐伏大型-超大型矿集区,在全国范围内更有可能存在相近大规模的铝土矿矿集区。

Long-term changes in sedimentary diatom assemblages and their environmental implications in the Changjiang(Yangtze) River estuary, China

Long-term data on diatom assemblages in a sediment core （60 cm） obtained from the Changjiang （Yangtze） River estuary were analyzed in order to assess the environmental changes that took place in the approximately 38 years （as determined by 210pb measurements）, i.e., between 1974 and 2012, of sediment accumulation. From the sediment core, 62 diatom taxa and genera were identified. The diatom biomass in the core generally increased beginning in the mid-1990s （core depth： 35 cm）, accompanied by a shift in the dominant species from Podosira stelliger and two species of Cyclotella （C. stylorum and C. striata） to Paralia sulcata, three species of Thalassiosira （ T. eccentria, I＂. oestrupii, and T. excentrica）, Actinoptychus undulates, and Thalassionema nitzschioides. The changes in both species diversity and abundance suggested that since the 1980s the estuary has undergone extensive eutrophication. This conclusion was supported by the increased proportion of planktonic species, another indicator of high nutrients inputs, in the Changjiang River estuary.

Diatom distribution as an environmental indicator in surface sediments of the West Philippine Basin

The distribution of diatoms from surface sediments of the West Philippine Basin was analyzed, with 68 species and varieties of diatoms from 26 genera identified. Diatom abundance varied spatially, with the absolute abundance of diatoms ranging from 0 to 3.4× 104 frustules/g. The seven tropical pelagic diatoms were Alveus marinus, Azpeitia africana, Azpeitia nodulifera, Hemidiscus cuneiformis, Hernidiscus cuneiformis var. ventricosus, Roperia tesselata and Rhizosolenia bergonii. The relative abundance of these species was greater than 20%, and their distribution pattern in the sediments was overlaid by the flow of the Kuroshio Current. Ethmodiscus rex was present at 159 stations, formed the most abundant and dominant species in the diatomaceous ooze, and thus referred to as Ethmodiscus ooze. Ethmodiscus rex was also a major contributor to primary production in the region. A principal component analysis was employed to explain the relationship between samples and variations in diatom species from the WPB. Four diatom assemblages were distinguished, representing different oceanographic conditions; their spatial distributions were closely related with the North Equatorial Current and Kuroshio Current patterns in the region. These diatom assemblages can therefore be useful in deciphering late Quaternary palaeoceanographic reconstructions of the West Philippine Basin.

Chemical Vapor Deposition Mechanism of Copper Films on Silicon Substrates

A versatile metal-organic chemical vapor deposition （MOCVD） system was designed and constructed. Copper films were deposited on silicon （100） substrates by chemical vapor deposition （CVD） using Cu（hfac）2 as a precursor. The growth of Cu nucleus on silicon substrates by H2 reduction of Cu（hfac）2 was studied by atomic force microscopy and scanning electron microscopy. The growth mode of Cu nucleus is initially Volmer-Weber mode （island）, and then transforms to Stranski-Rastanov mode （layer-by-layer plus island）. The mechanism of Cu nucleation on silicon （100） substrates was further investigated by X-ray photoelectron spectroscopy. From Cu2p, O1s, F1s, Si2p patterns, the observed C=O, OH and CF3/CF2 should belong to Cu（hfac） formed by the thermal dissociation of Cu（hfac）2. H2 reacts with hfac on the surface, producing OH. With its accumulation, OH reacts with hfac, forming HO-hfac, and desorbs, meanwhile, the copper oxide is reduced, and thus the redox reaction between Cu（hafc）2 and H2 occurs.