Influence of deposition rate on the properties of ZrO_2 thin films prepared in electron beam evaporation method

ZrO2 thin films were prepared in electron beam thermal evaporation method. And the deposition rate changed from 1.3 to 6.3 nm/s in our study. X-ray diffractometer and spectrophotometer were employed to characterize the films. X-ray diffraction (XRD) spectra pattern shows that films structure changed from amorphous to polycrystalline with deposition rate increasing. The results indicate that internal stresses of the films are compressive in most case. Thin films deposited in our study are inhomogeneous, and the inhomogeneity is enhanced with the deposition rate increasing.     

激光驱动高亮度电子束源

采用激光驱动光阴级和１００ｋＶ直流加速间隙可产生宽度为５０～１００ｐｓ的高亮度脉冲电子束．该装置主要由光阴极制备室和直流加速间隙组成．可以用化学气相沉积、离子注入和离子束增强沉积等方法制备光阴极．通过用ＥＧＵＮ和ＰＯＩＳＳＯＮ程序模拟,给出了直流加速间隙的物理设计．光源采用一台主被动双锁的Ｎｄ:ＹＡＧ激光器,可工作在１０６４、５３２和２６６ｎｍ三个波长,重复频率为１０Ｈｚ．此外,也论述了光阴极制备室与超与腔结合的超导高亮度注入器的有关问题. A DC high brigytness laser driven by photoemissive electron gun is being developed at Peking University,in order to produce 50～100ps electron bunches of high quality.The gun consists of a photocathode preparation chamber and a DC acceleration cavity.Different ways of fabricating photocathode,such as chemical vapor deposition,ion beam implantation and ion beam enhanced deposition,can be adopted.The acceleration gap is designed with the aid of simulation codes EGUN and POISSON,100kV DC high voltage is...     

Deposition of TiN Films by Novel Filter Cathodic Arc Technique

A straight magnetic filtering arc source is used to deposit thin films of titanium nitride. The properties of the films depend strongly on the deposition process. TiN films can be deposited directly onto heated substrates in a nitrogen atmosphere or onto unbiased substrates by condensing the Ti^＋ ion beam in about 300 eV N2^＋ nitrogen ion bombardment. In the latter case, the film stoichiometry is varied from an N：Ti ratio of 0.6-1.1 by controlling the arrival rates of Ti and nitrogen ions. Meanwhile, simple models are used to describe the evolution of compressive stress as function of the arrival ratio and the composition of the ion-assisted TiN films.     

Growth-Parameter Spaces and Optical Properties of Cubic Boron Nitride Films on Si（001）

Cubic boron nitride （c-BN） films were deposited on Si（001） substrates in an ion beam assisted deposition （IBAD） system under various conditions, and the growth parameter spaces and optical properties of c-BN films have been investigated systematically. The results indicate that suitable ion bombardment is necessary for the growth of c-BN films, and a well defined parameter space can be established by using the P/a-parameter. The refractive index of BN films keeps a constant of 1.8 for the c-BN content lower than 50%, while for c-BN films with higher cubic phase the refractive index increases with the c-BN content from 1.8 at χc =50% to 2.1 at χc = 90%. Furthermore, the relationship between n and p for BN films can be described by the Anderson-Schreiber equation, and the overlap field parameter γ is determined to be 2.05.     

Microstructure and optical properties of Ge films prepared by ion beam assisted deposition

Germanium （Ge） films are prepared on BK7 glass and multispectral zinc sulfide （m-ZnS） substrates by ion beam assisted deposition （IBAD）. The effects of substrate temperature, deposition rate, and ion energy on the microstructure and optical properties of the films are investigated. It can be concluded that Ge film deposited with higher rate or ion energy has more optical absorption, while ion energy below 150 eV helps to reduce film absorption. Film refractive index increases with film deposition rate and bombardment ion energy while it is below 300 eV. And higher growth rate or bombardment ion energy can weaken film diffraction intensity.     

Structure,conductivity, and ion emission properties of RbAg_4I_5 solid electrolyte film prepared by pulsed laser deposition

We fabricated a silver ion emitter based on the solid state electrolyte film of RbAg_4 I_5 prepared by pulsed laser deposition. The RbAg_4 I_5 target for PLD process was mechano-chemically synthesized by high-energy ball milling in Ar atmosphere using β-AgI and RbI as raw materials. The ion-conducting properties of RbAg_4 I_5 were studied by alternating current(AC) impedance spectroscopy and the ionic conductivity at room temperature was estimated 0.21 S/m. The structure, morphology, and elemental composition of the RbAg_4 I_5 film were investigated. The Ag~+ ion-conducting property of the prepared superioni-conductor film was exploited for ion–beam generation. The temperature and accelerating voltage dependences of the ion current were studied. Few nA current was obtained at the temperature of 196?C and the accelerating voltage of 10 kV.     

Microstructure and photoluminescence of Er-doped SiOx films synthesized by ion beam assisted deposition

Er-doped SiO_x films were synthesized at 500℃ by ion beam assisted deposition technique and annealed at 800 and 1100℃ for 2h in the air atmosphere. The analysis by using energy dispersive x-ray spectroscopy showed that the ratio of Si to O decreased from 3 in the as-deposited films to about 1 in the annealed films. The investigation by using transmission electron microscopy and x-ray diffraction indicated that annealing induces a microstructure change from amorphous to crystalline. The grain sizes in the films were about 10 and 40nm when annealed at 800 and 1100℃, respectively. The films annealed at temperatures of 800 and 1100℃ exhibited a sharp photoluminescence (PL) at 1.533μm from the Er centres when pumped by 980nm laser. The influence of microstructure and grain size on the PL from Er-doped SiO_x films has been studied and discussed.     

Preparation and Characteristics of GaN Films on Freestanding CVD Thick Diamond Films

Prefer-oriented and fine grained polycrystalline GaN films are prepared by plasma enhanced metal organic chemical vapour deposition on nucleation surfaces of freestanding thick diamond films. The characteristics of the GaN films are characterized by x-ray diffraction, reflection high energy electron diffraction and atomic force microscopy. The results indicate that the structure and morphology of the films are strongly dependent on the deposition temperature. The most significant improvements in morphological and structural properties of GaN films are obtained under the proper deposition temperature of 400°C.     

Commissioning of electron cooling in CSRe

The 400 MeV/u 12C6＋ ion beam was successfully cooled by the intensive electron beam near 1 A in CSRe.The momentum cooling time was estimated near 15 s.The cooling force was measured in the cases of difierent electron beam profiles,and the difierent angles between the ion beam and electron beam.The lifetime of the ion beam in CSRe was over 80 h.The dispersion in the cooling section was confirmed as positive close to zero.The beam sizes before cooling and after cooling were measured by the moving screen.The beam diameter after cooling was about 1 mm.The bunch length was measured with the help of the signals from the beam position monitor.The difiusion was studied in the absence of the electron beam.     

Oxygen Pressure Dependence of Properties of Epitaxial LaAlO3 Films Grown on Si （100）

Heteroepitaxial LaAlO3 films were grown on a SrTiO3/Si (100) substrate by laser molecular beam epitaxy under different oxygen pressures, and their properties such as crystallinity and electrical characteristics were experimentally investigated using the various measurement methods. The results show that most properties depend mainly on the deposition oxygen pressure. The crystallinity and the C-V and I-V characteristics can be greatly improved with the increasing oxygen deposition pressure. Moreover, after annealed at 1050~C in N2 ambient, the C-V and I-V characteristics of LAO films deposited at the lower oxygen pressure are also improved due to the decrease of oxygen vacancies in LAO films.     

离子束技术对氧化铪薄膜性能的影响

 在基底清洗、薄膜沉积和薄膜后处理三个阶段均采用离子束技术,制备了氧化铪薄膜,并对薄膜的光学性能、表面特性和激光损伤阈值特性进行测试和研究。结果表明,利用离子束技术清洗基底可以增强表面吸附;离子束辅助沉积在合适离子束能量下可以得到高堆积密度、高损伤阈值的薄膜;离子束后处理氧化铪薄膜可以降低表面粗糙度,改善抗激光损伤阈值。说明在三个薄膜制备阶段同时采用合适的离子束参数可以制备出结构致密、阈值高、表面粗糙度好的氧化铪薄膜。     

离子束技术对氧化铪薄膜性能的影响

在基底清洗、薄膜沉积和薄膜后处理三个阶段均采用离子束技术,制备了氧化铪薄膜,并对薄膜的光学性能、表面特性和激光损伤阈值特性进行测试和研究。结果表明,利用离子束技术清洗基底可以增强表面吸附;离子束辅助沉积在合适离子束能量下可以得到高堆积密度、高损伤阈值的薄膜;离子束后处理氧化铪薄膜可以降低表面粗糙度,改善抗激光损伤阈值。说明在三个薄膜制备阶段同时采用合适的离子束参数可以制备出结构致密、阈值高、表面粗糙度好的氧化铪薄膜。     

电子束、离子辅助和离子束溅射三种工艺对光学薄膜性能的影响

 运用电子束、离子辅助和离子束溅射三种镀膜工艺分别制备光学薄膜，包括单层氧化物薄膜和增透膜，然后采取一系列测试手段，如Zygo轮廓仪、原子力显微镜、表面热透镜技术和X射线衍射等技术，来分析和研究不同的工艺对这些薄膜性能的不同影响，以判断合理的沉积工艺。     

质量分离低能离子束沉积碳膜及离子轰击效应

用质量分离的低能离子束沉积技术得到了非晶碳薄膜,X射线衍射、Raman谱以及俄歇深度谱的线形表明,此种非晶碳膜中镶嵌着金刚石颗粒.碳离子的浅注入是该碳膜SP³形成的主要机理.从一个侧面说明了化学气相沉积法中偏压预处理增加金刚石成核的主要原因是因为离子轰击效应. 关键词： 非晶碳 离子轰击 质量分离低能离子束     

离子束增强沉积制备p型氧化锌薄膜及其机理研究

采用离子束增强沉积方法在Si和SiO₂/Si衬底上制备In-N共掺杂ZnO薄膜(INZO)，溅射靶是用ZnO和2 atm% In₂O₃粉体均匀混合并压制而成，在氩离子溅射ZnO靶的同时，氮、氩混合离子束垂直注入沉积的薄膜.实验结果显示INZO薄膜具有(002)的择优取向，并且为p型导电，电阻率最低为0.9Ωcm.薄膜在氮气、氧气气氛下退火，对薄膜的结构和电学特性与成膜和退火条件的关系进行了分析. 关键词： 氧化锌薄膜 p型掺杂 离子束增强沉积     

电子束、离子辅助和离子束溅射三种工艺对光学薄膜性能的影响

运用电子束、离子辅助和离子束溅射三种镀膜工艺分别制备光学薄膜,包括单层氧化物薄膜和增透膜,然后采取一系列测试手段,如Zygo轮廓仪、原子力显微镜、表面热透镜技术和X射线衍射等技术,来分析和研究不同的工艺对这些薄膜性能的不同影响,以判断合理的沉积工艺。     

Advanced ion beam technology for versatile oxide thin film formation

Various oxide films, such as SnO₂, In₂O₃, Al₂O₃, SiO₂, ZnO, and Sn-doped In₂O₃ (ITO) have been deposited on glass and polymer substrates by advanced ion beam technologies including ion-assisted deposition (IAD), hybrid ion beam, ion beam sputter deposition (IBSD), and ion-assisted reaction (IAR). Physical and chemical properties of the oxide films and adhesion between films and substrates were improved significantly by these technologies. By using the IAD method, non-stoichiometry, crystallinity, and microstructure of the films were controlled by changing assisted oxygen ion energy and arrival ratio of assisted oxygen ion to evaporated atoms. IBSD method has been carried out for understanding the growth mode of the films on glass and polymer substrate. Relationships between microstructure and electrical properties in ITO films on polymer and glass substrates were intensively investigated by changing ion energy, reactive gas environment, substrate temperature, etc. Smooth-surface ITO films (R_rms ⩽ 1 nm and R_p−v ⩽ 10 nm) for organic light-emitting diodes were developed with a combination of deposition conditions with controlling microstructure of a seed layer on glass. IAR surface treatment enormously enhanced the adhesion of oxide films to polymer substrate. In the case of Al₂O₃ and SiO₂ films, the oxygen and moisture barrier properties were also improved by IAR surface treatment. The experimental results of the oxide films prepared by the ion beam technologies and its applications will be represented in detail.     

Post-annealing influence on properties of N-In codoped ZnO thin films prepared by ion beam enhanced deposition method

N-In codoped ZnO thin films were prepared by ion beam enhanced deposition method (IBED) and were annealed in nitrogen and oxygen ambient after deposition. The influence of post-annealing on structure, electrical and optical properties of thin films were investigated. As-deposited and all post-annealed samples showed preferential orientation along (0 0 2) plane. Electrical property studies indicated that the as-deposited ZnO film showed p-type with a sheet resistance of 67.5 kΩ. For ZnO films annealed in nitrogen with the annealing temperature increasing from 400 to 800 °C, the conduction type of the ZnO film changed from p-type to n-type. However, for samples annealed in oxygen the resistance increased sharply even at a low annealing temperature of 400 °C and the conduction type did not change. Room temperature PL spectra of samples annealed in N₂ and in O₂ showed UV peak located at 381 and 356 nm, respectively.     

Influence of deposition conditions on the microstructure of oxides thin films

Thin films of ZrO₂, HfO₂ and TiO₂ were deposited on kinds of substrates by electron beam evaporation (EB), ion assisted deposition (IAD) and dual ion beam sputtering (DIBS). Then some of them were annealed at different temperatures. X-ray diffraction (XRD) was applied to determine the crystalline phase and the grain size of these films, and the results revealed that their microstructures strongly depended on the deposition conditions such as substrate, deposition temperature, deposition method and annealing temperature. Theory of crystal growth and migratory diffusion were applied to explain the difference of crystalline structures between these thin films deposited and treated under various conditions.     

二氧化锆薄膜表面粗糙度的研究

采用电子束蒸发工艺,利用泰勒霍普森相关相干表面轮廓粗糙度仪,研究了不同基底粗糙度、不同二氧化锆薄膜厚度以及不同的离子束辅助能量下所沉积的二氧化锆薄膜的表面粗糙度。结果表明：随着基底表面粗糙度的增加,二氧化锆薄膜表面粗糙度呈现出先缓慢增加,当基底的粗糙度大于10nm后呈现快速增加的趋势;随着二氧化锆薄膜厚度的增加,其表面均方根粗糙度（RMS）先减小后增大;随着辅助沉积离子能量的增加,其表面粗糙度呈现出先减小后增加的趋势。