硅上后热氧化钛膜制备氧化钛及其电学特性

采用在硅上磁控溅射金属钛膜再热氧化的工艺制备了多晶氧化钛薄膜.测量了Ag/TiOx/Si/Ag电容器的I-V和C-V特性.结果表明,氧化钛薄膜的厚度为150～250nm,其介电常数是40～87.随着氧化时间的缩短,氧化钛薄膜中的固定电荷减少,漏电特性得到改善.     

非晶氧化钛薄膜的电学特性研究

室温下,通过采用直流反应磁控溅射法在覆盖有氮化硅薄膜的单晶硅衬底上生长了厚度约为100nm的氧化钛薄膜。掠入射X射线衍射分析结果表明在室温下,不同氧分压下生长的氧化钛薄膜均具有非晶结构。分别采用场发射扫描电子显微镜、X射线光电子能谱对薄膜的表面和断面形貌以及薄膜的组分进行了分析和表征。对薄膜的电学特性测试发现非晶氧化钛薄膜在293～373K的温度范围内主要依靠热激发至扩展态中的电子导电。     

新型低温消气剂——一氧化钛

对钛和一氧化钛薄膜的吸附能力进行高真空和超高真空测量。在室温条件下,钛和一氧化钛簿膜用作消气剂时所表现的特性明显相同;而在低温下,一氧化钛薄膜的吸附活性及吸附能力则高于钛薄膜。在低温气氛中,一氧化钛的吸附活性达到1,吸附能力超过了4×10~(16)分子数/厘米~2。在液氮温度下,一氧化钛对氩气的吸附能力非常强:吸附活性达到0.17,吸附能力达10~(16)氩原子数/厘米~2。     

磁控溅射氧化钛薄膜在不同溅射温度下的光电性能研究

通过磁控反应溅射,在玻璃基底上制备了不同溅射温度下的氧化钛薄膜.通过对其光电性能的分析测试,探讨了溅射温度对氧化钛薄膜性能的影响.实验表明:低温溅射下,薄膜表面颗粒较小,结构较为疏松,高温溅射下,薄膜颗粒较大,薄膜表面颗粒出现团聚现象;随着溅射温度的升高,溅射速率减小;薄膜方阻减小,载流子浓度增大;溅射温度越高,薄膜在紫外可见光波段内透射越弱,光学带隙越小.     

磁控溅射氧化钛薄膜的电学特性研究

采用直流磁控溅射法在K9玻璃上制备了不同溅射温度和氧气流量的氧化钛(TiOx)薄膜.采用XPS、霍尔效应测试仪对薄膜的组份、载流子浓度和迁移率进行了测试,发现随着溅射氧气流量的增大,薄膜中的氧元素比例增大,载流子浓度减小,迁移率增大.分析了TiOx薄膜的电阻温度系数(TCR)与溅射温度和氧分压的关系,薄膜的电阻率从0....     

衬底温度对氧化钛薄膜的光学常数影响

采用沈阳CK-3高真空磁控溅射薄膜沉积设备在K9玻璃衬底上分别制备了衬底温度为150℃、200℃和250℃的氧化钛薄膜。XRD分析显示这三种温度制备的薄膜由于制备温度不高均没有明显衍射峰,为非晶薄膜。薄膜的光学常数由德国SENTECH SE 850型光谱型椭偏仪对薄膜测试得到,测试波长为300 nm～800 nm,采用Cauchy模型对测试结果进行拟合。结果发现随着制备衬底温度的增大,薄膜的折射率n和消光系数k都随着增大。在衬底温度从150℃增大到250℃时,薄膜的光学带隙从3.46 eV减小到3.02 eV。     

具有核壳结构材料的薄膜热敏电阻

分别采用巯基丙酸包覆的银(Ag/MPA)和十二胺包覆的硫化银(Ag2S/DDA)纳米粒子通过涂布和煅烧两步法在低温下获得了Ag2S-Ag核壳结构薄膜热敏电阻(NTCR)和Ag2S薄膜NTCR.使用扫描电子显微镜(SEM)对Ag2S-Ag核壳结构薄膜形貌进行了表征,使用X射线衍射光谱仪(XRD)与透射电子显微镜(TEM)对薄膜粒子组成、结晶度及结构进行了测试分析,研究了不同制备条件下的Ag2S-Ag核壳结构薄膜NTCR的热敏电阻系数(NTC)特性,根据ASTM D3359附着力测试标准分析了薄膜对基底的附着力.结果表明,所制备器件膜厚均匀且表面平整,器件的膜厚为1.64 μm,热敏系数B、零功率电阻温度系数αT和电子活化能Ea值分别为2 707 K,-32 234× 10-6K-1和5.533×10-3 eV,附着力测试评价达5A.与Ag2S薄膜NT-CR相比,Ag2S-Ag核壳结构薄膜NTCR具有更优的NTC特性,膜厚可控,具有高灵敏度及环境适应性.     

GAZO/Ag/GAZO透明导电薄膜的磁控溅射制备及光电性能优化

采用多源磁控溅射技术在玻璃衬底上制备了Ga、Al共掺杂氧化锌(GAZO)/Ag/GAZO透明导电薄膜。对比实验表明，通入O2溅射Ag能够提高薄膜在600～800 nm波段的光透射率。进一步优化后，发现在O2流量为1.0 sccm的条件下，12 nm的Ag获得连续结构，提升了GAZO/Ag/GAZO薄膜的光电性能。在空气中经150℃退火处理1 h,GAZO/Ag/GAZO薄膜的光电性能和结构性能都得到提升。退火后薄膜方块电阻为8.99Ω/sq,380～780 nm可见光波段平均透射率为98.17%，品质因子高达2260Ω^-1。该GAZO/Ag/GAZO透明导电薄膜显示出优异的光电性能，有望替代铟锡氧化物薄膜用于光电器件领域。     

ITO/Ag/AgNW新型复合透明导电薄膜性能研究

采用磁控溅射和湿法涂布技术制备了一种ITO/Ag/AgNW结构的新型复合透明导电薄膜。研究其光学、电学等性能发现:ITO/Ag/AgNW薄膜在400~700nm的平均透过率高于ITO/Ag/ITO薄膜,且方块电阻远小于ITO/Ag/ITO薄膜,达到6.9Ω/□;耐弯折性能测试后,其方块电阻约增加62%,达11.2Ω/□。研究结果表明,这种新型的复合透明导电薄膜具有低阻、高透及耐弯折良好的特性,在柔性显示领域具有一定的应用潜力。     

以低价态钛氧化物制备TiO2薄膜研究

试验以Ti2O3,Ti3O5和TiO2作为初始膜料,在ZZS700-6/G型真空镀膜机上采用O2-离子束辅助蒸发制备氧化钛薄膜.用XRD检测方法确定各种膜料和薄膜的相成分,并全面地分析了各种膜料的蒸发特性和薄膜;用分光光度计测量薄膜的透射率,并分析薄膜的光学性能.试验表明,在采用Ti2O3,Ti3O5和TiO2作为蒸发制备氧化钛薄膜时,钛的氧化物中存在Ti3O5固态同一蒸发相;各种膜料在蒸发时,发生分解,熔池中的物质成分逐渐转变成同一蒸发相成分,最终完全转变成同一蒸发相.     

Reflecting p-contact based on thin ITO films for AlGaInN flip-chip LEDs

A reflecting contact to a p-GaN layer, used in fabrication of blue flip-chip light-emitting diodes, has been produced by deposition of thin indium tin oxide (ITO) films by electron-beam evaporation. The high reflectance of the contact, which exceeds that of a Ni/Ag contact, provides a 15–20% increase in the external quantum efficiency of light-emitting crystals. The forward voltage drops for crystals with an ITO(5 nm)/Ag(220 nm) contact are comparable with the corresponding values for crystals with a Ni(1.5 nm)/Ag(220 nm) contact. The specific resistance of the contact with an ITO layer is 3.7 × 10^?3 Ω cm². It is shown that, for ITO films produced by the given method, the optimal thicknesses providing the best electrical and optical characteristics of the crystals are in the range 2.5–5.0 nm.

     

Fabrication of Ag nanoparticle/ZnO thin films using dual-plasma-enhanced metal-organic chemical vapor deposition (DPEMOCVD) system incorporated with photoreduction method and its application

We report a novel method to grow silver nanoparticle/zinc oxide (Ag NP/ZnO) thin films using a dual-plasma-enhanced metal-organic chemical vapor deposition (DPEMOCVD) system incorporated with a photoreduction method. The crystalline quality, optical properties, and electrical characteristics of Ag NP/ZnO thin films depend on the AgNO₃ concentration or Ag content and annealing temperature. Optimal Ag NP/ZnO thin films have been grown with a AgNO₃ concentration of 0.12 M or 2.54 at%- Ag content and 500 °C- rapid thermal annealing (RTA); these films show orientation peaks of hexagonal-wurtzite-structured ZnO (002) and face-center-cubic-crystalline Ag (111), respectively. The transmittance and resistivity for optimal Ag NP/ZnO thin films are 85% and 6.9×10⁻⁴ Ω cm. Some Ag NP/ZnO transparent conducting oxide (TCO) films were applied to InGaN/GaN LEDs as transparent conductive layers. The InGaN/GaN LEDs with optimal Ag NP/ZnO TCO films showed electric and optical performance levels similar to those of devices fabricated with indium tin oxide.     

PECVD法制备硅化钛膜的工艺研究

硅化钛薄膜由于电阻率低和其它一些良好特性,在VLSI的栅电极和互连线中显示出它潜在的优势。本文研究了用PECVD法制备硅化钛膜的卫艺。结果表明:所形成硅化钛膜的性质强烈地依赖于淀积工艺条件。还确定了典型工艺条件,并用俄歇电子能谱分析了硅化钛膜的组分。     

LED用石墨烯复合透明电极厚度组合的仿真与优化

为降低石墨烯(Gr)透明电极与p-GaN之间的肖特基势垒与接触电阻,进行了将银、金、镍和铂四种金属或氧化镍作为中间层引入它们两者之间的尝试。使用有限元方法模拟研究了Gr与金属或氧化镍的不同厚度组合对LED的光、热和电特性的影响。发现:透明导电层的透光率和LED芯片的表面温度均随石墨烯和金属或氧化镍厚度的增加而降低;1.5nm的Ag、Ni、Pt,1nm Au或1nm的NiO_x分别与3层(3L)Gr复合时为优化厚度组合,其中,1.5nm Ni/3L Gr为最佳Gr/金属复合透明电极。     

Development of the Self-Aligned Titanium Silicide Process for VLSI Applications

A manufacturable self-aligned titanium silicide process which simultaneously silicides both polysilicon gates and junctions has been developed for VLSI applications. The process produces silicided gates and junctions with sheet resistances of 1.0-2.0 Omega/square. This paper describes the application of the self-aligned titanium silicide process to NMOS VLSI circuits of the 64K SRAM class with 1-/spl mu/m gate lengths. Comparison of circuit yield data and test structure parameters from devices fabricated with and without the silicidation process has demonstrated that the self-aligned silicide process is compatible with both VLSI NMOS and CMOS technologies. The self-aligned titanium silicide process has some very significant manufacturing advantages over the more conventional deposited silicide on polysilicon technologies. In particular, the problems associated with etching and depositing a polycide gate stack are eliminated with the self-aligned process since the polycide etch is replaced with a much more straightforward polysilicon only etch. As gate lengths, gate oxide thicknesses, and source-drain junction depths are scaled, Iinewidth control, etch selectivity to the underlying gate oxide, and cross-sectional profile control become more critical. The stringent etch requirements are more easily satisfied with the self-aligned silicide process.     

Transparent Highly Ordered TiO2 Nanotube Arrays via Anodization of Titanium Thin Films

Titanium thin films, 400 nm to 1000 nm thick, fabricated by radio frequency (rf) sputter deposition are anodized in an electrolyte containing acetic acid and hydrofluoric acid to form optically transparent films of highly ordered titania nanotube arrays. Real‐time monitoring of the anodization current, at a fixed potential, is used to controllably eliminate the Ti layer underneath the titanium oxide nanotube array without disturbing the architecture. Fabrication variables critical to achieving the transparent nanotube‐array film include annealing temperature of the anodized, initially amorphous nanotube array and Ti‐film sputter deposition variables, including rate, film thickness, and substrate temperature. Structural investigations on the transparent nanotube arrays reveal only the presence of the anatase phase even after annealing at 500 °C. In contrast, both rutile and anatase phases were observed in films with a metal layer underneath the nanotubes and annealed in an oxygen ambient above 430 °C. Rutile growth occurs at the nanotube–metal interface as metal oxidation takes place during annealing. The average refractive index of the transparent nanotube‐array film is found to be 1.66 in the UV‐vis range, with a calculated porosity of 67 %; the bandgap is determined as 3.34 eV, with a bandgap tail extending to 2.4 eV.     

ZnO/Ag/ZnO多层膜的制备和性质研究

采用射频磁控溅射ZnO陶瓷靶和直流磁控溅射Ag靶的方法制备了ZnO/Ag/ZnO多层膜。用X射线衍射仪、紫外–可见分光光度计、四探针测试仪和金相显微镜对ZnO/Ag/ZnO薄膜的结构、光学透过率、方阻和稳定性进行了研究。结果表明,ZnO(60nm)/Ag/(10nm)/ZnO(60nm)薄膜呈现多晶结构,薄膜在520nm处的光学透过率高达87.5%,方阻Rs为6.2Ω/□。随着顶层ZnO薄膜厚度的增加,ZnO/Ag/ZnO薄膜的稳定性提高。     

Titanium silicide-silicon interface degradation during heat treatment

Thin titanium silicide films were grown on different silicon substrates by rapid thermal annealing in a nitrogen ambient. The silicide films were then annealed in a furnace at high temperature in a nitrogen ambient for various times. The effect of such heat treat-ment on the morphology of titanium silicide surface and the titanium silicide-silicon interface was studied. It is proposed that the morphological change is primarily due to the diffusion of silicon and/or dopant impurities via grain boundaries of the silicide. There is a strong correlation between the surface of the titanium silicide film and that of the titanium silicide-silicon interface.     

Interesting Evidence for Template‐Induced Ferroelectric Behavior in Ultra‐Thin Titanium Dioxide Films Grown on (110) Neodymium Gallium Oxide Substrates

The first evidence for room‐temperature ferroelectric behavior in anatase‐phase titanium dioxide (a‐TiO₂) is reported. Behavior strongly indicative of ferroelectric characteristics is induced in ultra‐thin (20 nm to 80 nm) biaxially‐strained epitaxial films of a‐TiO₂ deposited by liquid injection chemical vapor deposition onto (110) neodymium gallium oxide (NGO) substrates. The films exhibit significant orthorhombic strain, as analyzed by X‐ray diffraction and high‐resolution transmission electron microscopy. The films on NGO show a switchable dielectric spontaneous polarization when probed by piezoresponse force microscopy (PFM), the ability to retain polarization information written into the film using the PFM tip for extended periods (several hours) and at elevated temperatures (up to 100 °C) without significant loss, and the disappearance of the polarization at a temperature between 180 and 200 °C, indicative of a Curie temperature within this range. This combination of effects constitutes strong experimental evidence for ferroelectric behavior, which has not hitherto been reported in a‐TiO₂ and opens up the possibility for a range of new applications. A model is presented for the effects of large in‐plane strains on the crystal structure of anatase which provides a possible explanation for the experimental observations.