Deposition of Cu seed layer film by supercritical fluid deposition for advanced interconnects

The deposition of a Cu seed layer film is investigated by supercritical fluid deposition （SCFD） using H2 as a reducing agent for Bis（2,2,6,6-tetramethyl-3,5- heptanedionato） copper in supercritical CO2 （scCO2）. The effects of deposition temperature, precursor, and H2 concentration are investigated to optimize Cu deposition. Continuous metallic Cu films are deposited on Ru substrates at 190 ℃ when a 0.002 mol/L Cu precursor is introduced with 0.75 mol/L H2. A Cu precursor concentration higher than 0.002 mol/L is found to have negative effects on the surface qualities of Cu films. For a H2 concentration above 0.56 mol/L, the root-mean-square （RMS） roughness of a Cu film decreases as the H2 concentration increases. Finally, a 20-nm thick Cu film with a smooth surface, which is required as a seed layer in advanced interconnects, is successfully deposited at a high H2 concentration （0.75 tool/L）.

Effect of Seed Layer on the Orientation of Zinc Oxide Film on Silicon Substrate

The effect of seed layer on the orientation of ZnO film was investigated. Before the preparation of ZnO film using sol-gel method, seed layer of ZnO was prepared in a similar way using the precursor at a rather low concentration. Experiments show that the existence of seed layer can improve the orientation of the finally prepared ZnO film, while baking temperature, baking time and precursor concentration all have effects on the final results.

Effect of TiO_2 Seed Layer on 0.7Pb(Mg_(0.33)Nb_(0.67))O_3-0.3PbTiO_3 Thin Films Deposited by Radio Frequency Magnetron Sputtering

We have grown PbMg1/3Nb2/3O3-PbTiO3(PMN-PT) thin films by radio frequency(RF) sputtering deposition at 550 ℃-650 ℃ on Pt/Ti/SiO2/Si and TiO2/Pt/Ti/SiO2/Si substrates.The phase compositions and microstructure of thin films were characterized by X-ray diffraction(XRD) and scanning electric microstructure(SEM).The effect of the TiO2 seed layer on PMN-PT films was studied.

Effect of seed layers on the static and dynamic magnetic properties of CoIr films with negative effective magnetocrystalline anisotropy

The c-axis oriented hcp-Co_(81)Ir_(19)magnetic films were prepared on different seed layers(Ni,Cu,Ir,Pt,Au,and No seed).We systematically investigated the impact that surface-free energy and strain energy have on the orientation and defects and/or internal stress of the grains by increasing the lattice mismatch ratio.Moreover,the initial permeability and the natural resonance frequency were discussed in great detail using a comparison between calculated values and experimental values.We found that the almost unchanged 4πM_(s) andμ_(i) are not affected,while the changed H_(c),intrinsic K_(grain),and f_(r) are strongly dependent on the seed layer and seed layer material.Moreover,the extracted damping constant is sensitive to the defects and/or internal stress and orientation of the grains.Therefore,the soft magnetic properties and microwave properties are adjusted and optimized by seed layers with different materials.

Optimization and Evaluation of Sputtering Barrier/Seed Layer in Through Silicon Via for 3-D Integration

The barrier/seed layer is a key issue in Through Silicon Via （TSV） technology for 3-D integration. Sputtering is an important deposition method for via metallization in semiconductor process. However, due to the limitation of sputtering and a ＂scallop＂ profile inside vias, poor step coverage of the barrier/seed layer always occurs in the via metallization process. In this paper, the effects of several sputter parameters （DC power, Ar pressure, deposition time, and substrate temperature） on thin film coverage for TSV applications are investigated. Robust TSVs with aspect ratio 5 ： 1 were obtained with optimized magnetron sputter parameters. In addition, the influences of different sputter parameters are compared and the conclusion could be used as a guideline to select appropriate parameter sets.

Effects of seed layer on the performance of microcrystalline silicon germanium solar cells

Using plasma enhanced chemical vapor deposition（PECVD） at 13.56 MHz,a seed layer is fabricated at the initial growth stage of the hydrogenated microcrystalline silicon germanium(μc-Si1-xGex:H) i-layer.The effects of seeding processes on the growth ofμc-Si1-xGex:H i-layers and the performance ofμc-Si1-xGex:H p-i-n single junction solar cells are investigated.By applying this seeding method,theμc-Si1-xGex:H solar cell shows a significant improvement in short circuit current density(Jsc) and fill factor（FF） with an acceptable performance of blue response as aμc-Si:H solar cell even when the Ge content x increases up to 0.3.Finally,an improved efficiency of 7.05%is achieved for theμc-Si0.7Ge0.3:H solar cell.

Artificial synaptic and self-rectifying properties of crystalline(Na_(1-x)K_(x))NbO_(3)thin films grown on Sr_(2)Nb_(3)O_(10)nanosheet seed layers

Crystalline(Na_(1-x)K_(x))NbO_(3)(NKN)thin films were deposited on Sr_(2)Nb_(3)O_(10)/TiN/Si(S-TS)substrates at 370°C.Sr_(2)Nb_(3)O_(10)(SNO)nanosheets served as a template for the formation of crystalline NKN films at low temperatures.When the NKN film was deposited on one SNO monolayer,the NKN memristor exhibited normal bipolar switching characteristics,which could be attributed to the formation and destruction of oxygen vacancy filaments.Moreover,the NKN memristor with one SNO monolayer exhibited artificial synaptic properties.However,the NKN memristor deposited on two SNO monolayers exhibited self-rectifying bipolar switching properties,with the two SNO monolayers acting as tunneling barriers in the memristor.The conduction mechanism of the NKN memristor with two SNO monolayers in the highresistance state is attributed to Schottky emission,direct tunneling,and Fowler–Nordheim(FN)tunneling.The current conduction in this memristor in the low-resistance state was governed by direct tunneling and FN tunneling.Additionally,the NKN memristor with two SNO monolayers exhibited large ON/OFF and rectification ratios and artificial synaptic properties.Therefore,an NKN memristor with two SNO monolayers can be used for fabricating artificial synaptic devices with a cross-point array structure.

Steady-state solution growth of microcrystalline silicon on nanocrystalline seed layers on glass

The growth of polycrystalline silicon layers on glass from tin solutions at low temperatures is presented.This approach is based on the steady-state solution growth of Si crystallites on nanocrystalline seed layers, which are prepared in a preceding process step. Scanning electron microscopy and atomic force microscopy investigations reveal details about the seed layer surfaces, which consist of small hillocks, as well as about Sn inclusions and gaps along the glass substrate after solution growth. The successful growth of continuous microcrystalline Si layers with grain sizes up to several ten micrometers shows the feasibility of the process and makes it interesting for photovoltaics.

Influence of TiO_2 seeding layers on phase composition of lead magnesium niobate-lead titanate thin films prepared by RF magnetron sputtering

The influence of amorphous TiO_2 seeding layers on the phase composition of lead magnesium niobate-lead titanate(0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3,PMN-PT) films deposited on Pt/Ti/SiO2/Si substrate by RF magnetron sputtering was examined.The relation between seeding layer thickness and phase composition at different post annealing temperature was observed by XRD.The thickness of amorphous TiO2 seeding layer and post annealing temperature had remarkable effects on PMN-PT film phase composition.When amorphous seeding layer becomes thick,a new phase of Nb2O5 exists in the films.Only when the seeding layer thickness is suitable,the film with pure perovskite phase can be attained.

Fabrication of seeded substrates for layer transferrable silicon films

The layer transfer process is one of the most promising methods for low-cost and highly-efficient solar cells, in which transferrable mono-crystalline silicon thin wafers or films can be produced directly from gaseous feed-stocks. In this work, we show an approach to preparing seeded substrates for layer-transferrable silicon films. The commercial silicon wafers are used as mother substrates, on which periodically patterned silicon rod arrays are fabricated, and all of the surfaces of the wafers and rods are sheathed by thermal silicon oxide. Thermal evaporated aluminum film is used to fill the gaps between the rods and as the stiff mask, while polymethyl methacrylate （PMMA） and photoresist are used as the soft mask to seal the gap between the filled aluminum and the rods. Under the joint resist of the stiff and soft masks, the oxide on the rod head is selectively removed by wet etching and the seed site is formed on the rod head. The seeded substrate is obtained after the removal of the masks. This joint mask technique will promote the endeavor of the exploration of mechanically stable, unlimitedly reusable substrates for the kerfless technology.

Seed Free Growth of Aligned ZnO Nanowire Arrays on AZO Substrate

In the absence of commonly used seed layer, we can still successfully synthesized aligned ZnO nanowire arrays by the hydrothermal method. By using aluminum-doped zinc oxide(AZO) glass as a substrate, high-density and vertically aligned ZnO nanowires were synthesized directly on the substrate in the absence of the ZnO seed layer. The current-voltage curve indicated that the sample grown on AZO glass substrate in the absence of seed layer possesses better conductivity than that synthesized on FTO glass substrate with ZnO seed layer. Thus, a simplified, seed-free and low-cost experimental protocol was reported here for large-scale production of high quality ZnO nanowire arrays with promoted conductivity.

Magnetic properties and structure of Ni_80Fe_20/Ni_48Fe_12Cr_40 bilayer films deposited on SiO_2/Si(100) by electron beam evaporation

Ni80Fe20/Ni48Fe12Cr40 bilayer films and Ni80Fe20 monolayer films were deposited at room temperature on SiO2/Si（100） substrates by electron beam evaporation. The influence of the thickness of the Ni48Fe12Cr40 underlayer on the structure, magnetization, and magnetoresistance of the Ni80Fe20/Ni48Fe12Cr40 bilayer film was investigated. The thickness of the Ni48Fe12Cr40 layer varied from about 1 nm to 18 nm while the Ni80Fe20 layer thickness was fixed at 45 nm. For the as-deposited bilayer films the introducing of the Ni48Fe12Cr40 underlayer promotes both the （111） texture and grain growth in the Ni80Fe20 layer. The Ni48Fe12Cr40 underlayer has no significant influence on the magnetic moment of the Ni80Fe20/Ni48Fe12Cr40 bilayer film. However, the coercivity of the bilayer film changes with the thickness of the Ni48Fe12Cr40 undedayer. The optimum thickness of the Ni48Fe12Cr40 underlayer for improving the anisotropic magnetoresistance effect of the Ni80Fe20/Ni48Fe12Cr40 bilayer film is about 5 nm. With a decrease in temperature from 300 K to 81 K, the anisotropic magnetoresistance ratio of the Ni80Fe20 （45 nm）/Ni48Fe12Cr40 （5 nm） bilayer film increases linearly from 2.1% to 4.8% compared with that of the Ni80Fe20 monolayer film from 1.7% to 4.0%.

Structure and electrical properties of PZT/LNO/PT multilayer films on stainless steel substrates

PbZr0.53Ti0.47O3 (PZT) ferroelectric thin films were deposited on LaNiO3 (LNO) by sol-gel method. The PbTiO3 (PT) seed layer was depos-ited between the LNO buffer layer and stainless steel (SS) substrate, which effectively decreased the annealing temperature of LNO layer from 750 C to 650 C. X-ray diffraction (XRD) reveals that LNO layers with PT layer crystallize into a perovskite phase on annealing at 650 C for 10 min. PZT deposited on LNO buffer layer with PT seed layer exhibits good ferroelectric property.

高深宽比硅孔溅射铜种子层工艺的探索与研究

硅通孔技术(TSV)是当前非常热门的高密度封装技术,但由于常规薄膜沉积技术很难在高深宽比的硅孔内沉积铜、钨等金属种子层,硅通孔技术中存在深硅孔金属化困难的工艺问题。通过对倾斜溅射时铜原子二维非对心碰撞前后入射角度的变化关系进行模拟计算发现,当原子碰撞有能量损失时,入射到硅孔内的铜原子角度会发生改变,有助于其沉积在硅孔深处。本文利用负偏压辅助多个铜靶共焦溅射的方式,在不同深宽比的硅盲孔中沉积铜种子层,验证了该方法的可行性,并通过三靶共焦溅射成功在深宽比8∶1的硅孔内实现了铜种子层的沉积。

Influence of Temperature, Moisture, and Light Conditions on the Germination of Seeds of <i>Erythronium japonicum</i>Decne

Erythronium japonicum is a representative species of spring ephemeral, forest floor plants in substitution forests in Japan. Seed germination tests were conducted to observe the effects of temperature, light, and moisture content on the germination of E. japonicum. E. japonicum seeds did not germinate at constant temperatures of 5&#176C, 10&#176C, 15&#176C, 20&#176C, or 25&#176C. Seeds germinated at 5&#176C and 10&#176C after storage at 20&#176C for 1 or 2 months. Seed germinability was affected by desiccation to only 40% moisture content. Seeds germinated well in both light and dark conditions. Conditions under the leaf litter layer showed unique characteristics of temperature, light, and moisture content. The temperature was around 20&#176C under the leaf litter layer, even though it was 30&#176C above. The moisture content under the leaf litter layer was higher than that above. The leaf litter blocked out the sunlight. The temperature of 20&#176C necessary for E. japonicum germination occurred below, but not above, the leaf litter layer. The avoidance of decreasing in germinability from reduced seed moisture content in a short time is consistent with the high moisture conditions under the leaf litter layer. The leaf litter layer plays an important role in providing optimal conditions of temperature, light, and moisture content for the germination of E. japonicum seeds.

基于两步刻蚀工艺的锥形TSV制备方法

以硅通孔(TSV)为核心的2.5D/3D封装技术可以实现芯片之间的高速、低功耗和高带宽的信号传输。常见的垂直TSV的制造工艺复杂,容易造成填充缺陷。锥形TSV的侧壁倾斜,开口较大,有利于膜层沉积和铜电镀填充,可降低工艺难度和提高填充质量。在相对易于实现的刻蚀条件下制备了锥形TSV,并通过增加第二步刻蚀来改善锥形TSV形貌。成功制备了直径为10~40μm、孔口为喇叭形的锥形TSV。通过溅射膜层和铜电镀填充,成功实现了直径为15μm、深度为60μm的锥形TSV的连续膜层沉积和完全填充,验证了两步刻蚀工艺的可行性和锥形TSV在提高膜层质量和填充效果方面的优势。为未来高密度封装领域提供了一种新的TSV制备工艺,在降低成本的同时提高了2.5D/3D封装技术的性能。

基于分层叠加的机载LiDAR点云单木分割

【目的】提出一种基于分层叠加的单木分割算法,以充分利用高密度激光雷达点云信息,提高林分中下层单木分割精度。【方法】区别于传统将冠顶点作为聚类种子点的单木分割算法,基于分层叠加的单木分割算法以点云水平切片后各层的局部最大值为种子点进行分层聚类,并通过分层叠加与迭代优化,减少枝杈等因素导致的过分割现象,在保证上层树单木分割精度的同时提高对中下层单木的提取能力。【结果】基于分层叠加的单木分割算法在不同密度落叶松林分均有较高单木分割精度,提取单木与实测单木总体匹配成功率最高达94%,在中高密度林分匹配成功率最高达92%,相较其他算法,对中下层单木的匹配率可提高20%~40%;在单木树高提取精度方面,单木提取树高与实测树高相关系数为0.8,相对均方根误差为8.45%,提取冠幅与实测冠幅相关系数最高为0.83,相对均方根误差为16.5%。【结论】通过分层聚类、聚类种子点优化选取,充分利用林分各层次点云信息,可提高单木分割精度,为森林经营管理提供高精度数据支持。

水稻糊粉层蛋白酶体参与种子萌发的研究

种子萌发是植物进入营养生长阶段的关键性环节,在水稻(Oryza sativa L.)种子萌发过程中,糊粉层会合成并分泌一系列的酸性水解酶(如α-淀粉酶、蛋白酶)用于降解胚乳中的贮藏物质,为水稻幼苗生长提供营养。水稻种子贮藏蛋白的降解离不开蛋白酶体及蛋白酶的作用。为探究26S蛋白酶体、20S蛋白酶体及其亚基PBA1参与GA对萌发水稻种子糊粉层中贮藏蛋白的调节过程,本研究以水稻杂交种特优128为试验材料,通过采用酶联免疫吸附技术、实时荧光定量PCR技术等方法,检测26S蛋白酶体、20S蛋白酶体及PBA1的活性和OsPBA1转录水平,以及总蛋白含量的变化。结果表明:GA明显促进糊粉层细胞中贮藏蛋白的降解,加快水稻种子的萌发;而在GA合成受阻时,糊粉层细胞中贮藏蛋白的降解进程延缓,从而延迟水稻种子的萌发。正常培养条件下,水稻种子糊粉层中26S蛋白酶体活性和20S蛋白酶体活性的峰值分别出现在6 d和7 d,而OsPBA1表达水平及PBA1活性则在5 d和8 d均呈现峰值。进一步研究表明,GA可以诱导PBA1、20S蛋白酶体及26S蛋白酶体的活性,从而加快种子萌发的进程;而在26S蛋白酶体活性抑制剂MG132处理下,抑制了萌发水稻种子的生长,但提高了20S蛋白酶体和PBA1的活性。以上研究初步揭示了26S蛋白酶体在GA调节水稻种子糊粉层贮藏蛋白降解中的作用及其对种子萌发的影响。

匙叶翼首花种子低温层积过程中内源抑制物及激素变化研究

【目的】探究低温层积过程中匙叶翼首花(Pterocephalus hookeri)种子生理生化变化与休眠解除的内在联系。【方法】通过低温层积处理(60 d)解除匙叶翼首花种子休眠,观测不同层积时间种子发芽率、内源抑制物及赤霉素(GA)、吲哚乙酸(IAA)和脱落酸(ABA)的活性变化。【结果】在低温层积过程中,匙叶翼首花种子发芽率在层积后期(45~60 d)显著提高(P<0.05);在层积后,GA含量显著升高(P<0.05),萌发促进物和抑制物比例(GA/ABA、IAA/ABA、GA+IAA/ABA)也呈升高趋势;种子发芽率与GA显著正相关(P<0.05)。【结论】匙叶翼首花种子内部存在内源抑制物;匙叶翼首花种子浸提液随着层积时间的延长,对种子发芽率、根长和胚轴长的抑制先增强后减弱;内源激素比例平衡及GA含量的上升也是匙叶翼首花种子解除休眠的关键因素。

不同处理对轮台白杏种子发芽及幼苗生长的影响

【目的】掌握轮台白杏种子的最佳育苗方法,为高效科学育苗提供技术支撑,为揭示杏休眠机理提供理论依据。【方法】以轮台白杏种子为研究对象,设置激素法、温汤浸种法、低温层积法、激素+低温层积法打破种子休眠,统计发芽率,将萌发的种子播种到土壤中,30 d后测定幼苗特性。【结果】1)GA_(3)和温汤浸种处理不去皮种子,发芽率很低,表明轮台白杏具有种皮休眠特性。带壳轮台白杏种子经低温层积80 d才开始萌发,说明轮台白杏具有种壳休眠特性。2)在不同处理中,有两个处理方法发芽率及出苗率均较高,其中500 mg/L的GA_(3)处理半去皮轮台白杏种子,发芽率高达94.00%,出苗率高达88.00%,种苗根系发达,不易徒长,育苗成本最低,每千株为276元,育苗效率最高。温汤浸种轮台白杏种子在50℃浸种全去皮轮台白杏种子30 min,发芽率和出苗率均较高,分别为98.00%和84.00%,成本较低,效率较高。低温层积带壳种子120 d时发芽率最高为80.67%,所有低温层积处理出苗率低于70%,育苗成本较高,效率最低。3)先用激素浸泡种24 h,后层积综合处理发现,轮台白杏种子发芽率及出苗率均不高,且成本最高,育苗效率不高。【结论】杏具有种皮、种壳休眠特性。500 mg/L的GA_(3)浸泡半去皮种子24 h与50℃浸种全去皮轮台白杏种子30 min,育种成本较低,效率较高,均可用作生产中的育苗方法。