沉积在硅尖上的氮化硼薄膜的场发射特性

利用射频磁控溅射方法,在硅尖上沉积了氮化硼（BN）薄膜．红外光谱分析表明,BN薄膜结构为六角BN（h-BN）相（1380cm^-1和780cm^-1）．在超高真空系统中测量了BN薄膜的场发射特性,与沉积在硅片上的BN薄膜比较,沉积在硅尖上的BN薄膜的场发射特性明显提高．开启电场为8V／μm,最高发射电流为300μA／cm^2．沉积在硅尖上的BN薄膜的场发射FN曲线为两段直线,这可能是由于电子发射源于硅尖的尖部和根部造成的．     

工作气压对氮化硼薄膜场发射特性的影响

利用射频磁控溅射方法，在n型(100)Si基底上沉积了氮化硼(BN)薄膜，并在超高真空系统中测量了BN薄膜的场发射特性．研究发现，沉积时工作气压的变化对BN薄膜的场发射特性有很大影响，工作气压为2Pa时沉积的BN薄膜样品的场发射特性较好，其阈值电场为6V/μm，场发射电流为320μA／cm^2．F—N曲线表明，在外加电场的作用下，电子是通过隧道效应穿透BN薄膜表面势垒发射到真空的．     

金刚石薄膜场发射述评

介绍了金刚石薄膜的场发射机理,从理论和实验上分析了改进其场发射特性的观点和方法,结果证明:减小金刚石晶体尺寸以及在金刚石薄膜中掺杂一定量的杂质原子有助于改善金刚石薄膜的场发射性能.     

射频磁控溅射中偏压对薄膜污染的影响

薄膜溅射过程中杂质污染问题是影响薄膜质量的重要因素,会造成薄膜的吸收和散射损耗增大、结合力下降,形成针孔等。采用射频磁控溅射沉积氧化铝薄膜时,发现在不同负偏压条件下,真空室内的金属离子会造成不同程度薄膜污染,采用XPS对污染物进行了测试表征,并对污染来源进行了分析,最后得出结论：在较高负偏压条件下真空室器壁金属溅射,是造成镀制氧化铝薄膜的重要污染源。     

碳纳米管薄膜的场发射特性研究

碳纳米管薄膜是一种能应用于场发射平面显示器等器件中的新型冷阴极材料。该文用Ni作为催化剂,采用催化热解法在硅片上制备了多壁碳纳米管薄膜场发射阴极,反应气体为乙炔、氢气和氮气。用SEM和TEM分析了其结构,证明了碳纳米管的直径在50~70 nm间。进而采用二极管结构,在优于10-4Pa的真空度下,测试了它的场发射特性,理论分析表明碳纳米管薄膜的场发射实际上来源于突出于薄膜表面的部分碳纳米管顶端。该阴极的开启电场为8 V/mm;在11 V/mm时测试到了最大的发射电流密度2 mA/cm2,满足场发射平面显示器的要求。     

偏压对磁控溅射Cr-N薄膜组织及性能影响

采用磁控溅射离子镀制备Cr-N薄膜,研究基体偏压对Cr-N薄膜组织结构和性能的影响。分别用辉光放电光电子谱(GDOES)、场发射扫描电镜(FESEM)和X射线衍射(XRD)分析薄膜成分和组织结构,显微硬度计测量薄膜硬度。结果表明,薄膜为非化学计量比的Cr-N薄膜,N/Cr原子比均小于0.25,薄膜主要以Cr的衍射峰为主。在偏压达到60 V后薄膜显示了较高的硬度(25 GPa),其归因于离子轰击导致的薄膜的致密度的提高。偏压超过60 V后,致密度达到饱和,硬度增加不明显。     

碳纳米管薄膜的制备及处理对场发射特性的影响

采取直接在硅片上真空蒸镀NiCr合金作为催化剂,用化学气相沉积法制备了碳纳米管薄膜。并采用H2等离子体球处理碳纳米管薄膜,测试其场发射特性,并与未经处理的碳纳米管薄膜进行了比较,得到碳纳米管薄膜开启场强有所降低,为1~1.2 V/μm。对碳纳米管薄膜进行老炼处理,最大场发射电流由12.3 μA提高到34 μA。     

射频磁控溅射AlN薄膜的场发射性能研究

氮化铝(Al N)是一种宽禁带深紫外半导体材料,其良好的性能可作为紫外固态光源。采用射频磁控溅射法,在p型Si(100)衬底上制备了Al N薄膜。通过X射线衍射分析(XRD)、紫外-可见光光谱(UV-Vis)、场发射测试对制备的Al N薄膜进行了测试分析,针对薄膜生长特性对光吸收的影响及其场发射性能进行了研究。结果显示:在Si衬底上成功的制备了高度(002)取向的Al N薄膜,薄膜在230~250nm间有强紫外吸收,阈值电场为6.39V/μm。场发射测试结果表明,磁控溅射法制备的Al N薄膜具备良好的场发射性。     

表面覆盖氮化硼膜的金刚石膜的场发射特性

利用热丝化学气相沉积（HFCVD）方法在Si衬底上生长了4μm厚的金刚石膜,然后利用射频磁控溅射方法在金刚石膜上沉积了100nm厚的六角氮化硼（h—BN）薄膜．在超高真空系统中测试了覆盖氮化硼（BN）薄膜前后金刚石膜的场发射特性,结果表明覆盖BN薄膜后的金刚石膜的场发射特性明显提高,开启电场由14V／μm升到8V／μm．F—N曲线表明,覆盖BN薄膜后的金刚石膜在强电场区域的场增强因子有所降低,这可能归因于场发射点随着电场的增强而改变．     

MPCVD实验条件对碳氮纳米管薄膜场发射性能的影响

通过正交设计试验法研究了微波等离子体化学气相沉积(MPCVD)实验条件对碳氮纳米管薄某》⑸湫阅艿挠跋?结果表明,当微波功率为1 500W、反应气压为8.5kPa、甲烷、氮气和氢气的流量比为8:20:80时,制备的碳氮纳米管薄膜场发射特性最好,其开启电场强度为3.2 V/μm,电场强度为8.0V/μm时的电流密度为3.5 mA/cm2.     

Influence of bath composition on the electrodeposition of cobalt-molybdenum amorphous alloy thin films

Cobalt-molybdenum (Co-Mo) amorphous alloy thin films were deposited on copper substrates by the electrochemical method at pH 4.0. Among the experimental electrodeposition parameters, only the concentration ratio of molybdate to cobalt ions ([ MoO2-4 ]/[CO2 ]) was varied to analyze its influence on the mechanism of induced cobalt-molybdenum codeposition. Voltammetry was one of the main techniques, which was used to examine the voltammetric response, revealing that cobalt-molybdenum codeposi-tion depended on the nature of the species in solution. To correlate the type of the film to the electrochemical response, various co-bait-molybdenum alloy thin films obtained from different [ MoO2-4]/[Co2 ] solutions were tested. Crack-free homogeneous films could be easily obtained from the low molybdate concentrations ([ MoO2-4]/[Co2 ]≈0.05) applying low deposition potentials.Moreover, the content of molybdenum up to 30wt% could be obtained from high molybdate concentration; in this case, the films showed cracks. The formation of these cracked films could be predicted from the observed distortions in the curves of electric cur-rent-time (j-t) deposition transients. The films with amorphous stmeture were obtained. The hysteresis loops suggested that the easily film were obtained when the deposition potential was -1025 mV, and [ MoO2-4]/[Co2 ] was 0.05 in solution, which exhibited a nicer soft-magnetic response.     

绝缘体上硅锗薄膜的退火研究

绝缘体上硅锗是近年来受到人们广泛关注和研究的新型微电子材料,它以其独特的全介质隔离结构,可为研发新型的超高速、低功耗、抗辐射、高集成度硅基器件和芯片提供一种新的解决方案,有希望成为突破体硅器件的物理极限、在深亚微米超大规模集成电路芯片主流技术中获得广泛地应用。介绍了我们制备绝缘体上硅锗薄膜的方法和结果。     

Effect of interface layers on electron field emission properties of amorphous diamond films

Hydrogen-free high sp~3 content amorphous diamond (AD) films are deposited on three different substrates——Au-coated Si (Au/Si), Ti-coated Si (Ti/Si) and Si wafers. Electron field emission properties and fluorescent displays of the above AD films are studied by using a sample diode structure. The compositional profile of the interfaces of AD/Ti/Si and AD/Si is examined by using secondary ions mass spectroscopy (SIMS). Because of the reaction and interdiffusion between Ti and C, the formation of a thin TiC intermediate layer is possible between AD film and Ti/Si substrate. The field emission properties of AD/Ti/Si are sufficiently improved, especially its uniformity. A field emission density of 0.352 mA/cm~2 is obtained under an electric field of 19.7 V/μm. The value is much more than that of AD/Au/Si and AD/Si under the same electric field.     

Influence of residual stress on the phase equilibrium of Ti(C_xN_y) thin films

In order to provide a theoretic basis for the research of Ti(CxNy) thin films, the thermodynamic database of Ti-C-N ternary system is established and the phase diagram sections are calculated. In addition to the assessed thermodynamic properties of Ti-C-N system, the influence of the residual strain energy of Ti(CxNy) thin films on the phase equilibria is analyzed. The classical formula for calculating the elastic strain energy is expressed into a Redlich-Kister form in order to perform the thermodynamic and equilibrium calculations using the Thermo-Calc software. Isothermal sections at 900 and 1100 K are calculated with this database and compared with those calculated without considering the residual stress. As a result, with the addition of strain energy δ-fcc Ti(CxNy) phase area shrinks. It is therefore concluded that with the influence of the residual stress in Ti(CxNy) thin solid film, the precipitation of pure 5 film requires more precise control of composition.     

Ductility of metal thin films in flexible electronics

Flexible, large area electronics using various organic and inorganic materials are beginning to show great promise. During manufacture and service, large deformation of these hybrid materials will pose significant challenges in terms of high performance and reliability. A deep understanding of the ductility or flexibility of macroelectronics becomes one of the major issues that must be addressed urgently. This paper describes the current level of understanding on the thin-film ductility, both free-standing and substrate-supported, and relevant influencing factors. Supported by the National Basic Research Program of China (Grant No. 2004CB619303), the 111 Project of China (Grant No. B06025), and the Science and Technology Key Project from Ministry of Education of China (Grant Nos. 02182, 03182)     

3C—SiC单晶薄膜的干法刻蚀研究

以四氟化碳（CF4）和CF4 O2作为刻蚀气体,对外延3C-SiC单晶薄膜进行了系统的等离子体刻蚀研究。结果表明薄膜刻蚀速率在气体流量一定的情况下与O2/CF4流量比有关：当O2/CF4流量比为40%左右时,刻蚀速率达到量大值;O2/CF4流量比低于40%,不仅刻蚀速度降低而且还在被刻蚀样品表面形成暗表面层,俄歇能谱（AES）分析表明暗层为富C表面的的残余SiC,AES分析还证实改变工艺条件可以消除富C表面的文中还给出了经图形刻蚀后的样品的表面形貌（SEM）照片。     

磁控溅射法生长ZnO薄膜的结构和表面形貌特性

采用射频磁控溅射方法,在Si（111）和玻璃基片上制备ZnO薄膜。研究衬底温度和基片类型对薄膜结构、表面形貌的影响。结果显示,所有ZnO薄膜沿c轴择优生长,同种基片类型上生长的薄膜,随着衬底温度升高,（002）衍射峰强度和表面粗糙度增高;相同衬底温度下生长的ZnO薄膜,Si基片上制备的薄膜（002）衍射峰强度和表面粗糙度小于玻璃片上的。基片类型影响薄膜应力状态,玻璃片上制备的ZnO薄膜处于张应变状态,Si基片上的薄膜处于压应变状态;对于同种基片类型上生长的ZnO薄膜,衬底温度升高,应力减小。Si衬底上、300℃下沉积的薄膜颗粒尺寸分布呈正态。     

Highfield effects of layered perovskite ferroelectric thin films

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磁性薄膜自旋重取向的机制

采用Monte Carlo方法,使用微观电子自旋模型和具有偶极相互作用的Heisenberg模型,对16×16二维平方格子的磁性系统自旋重取向现象进行了研究.发现在一定参数下,系统呈现出包含4个不同区域的磁化曲线.从理论上再现了系统从垂直磁化向面内磁化转变时的宏观磁矩的丢失现象,得到了与实验观测相一致的结果.通过计算系统的自旋组态和能量特征,对产生这种现象的机制进行了分析.