金刚石薄膜为掩膜离子束室温溅射可控制备硅纳米圆锥阵列

以金刚石薄膜为掩膜,采用低能Ar+室温倾角溅射的方法制备密度和形貌可控的硅纳米圆锥阵列.扫描电子显微镜(SEM)结果表明,离子束溅射后得到的硅纳米圆锥密度与作为掩膜的金刚石薄膜颗粒密度相当;硅纳米圆锥的形貌与离子束入射角有密切关系,随着入射倾角由30°增大到75°;得到的硅纳米圆锥的锥角由73°减小到23°,其长径比从500 am/360 nm增大到2400nm/600nm.由于金刚石比硅材料的溅射速率更低,因此以金刚石薄膜为掩膜可以制备较大长径比的硅纳米圆锥阵列;随着入射角的增大,离子束溅射诱导的表面原子有效扩散系数减小和溅射速率增大是硅纳米圆锥的锥角减小、长径比增大的主要原因.     

背散射法测定低能氩离子对金的溅射率

本文用背散射方法测定了300—1200eV不同能量的氩离子对金的溅射率。实验测得的背散射能谱用两种不同的方法(能量损失和面积法)处理,结果表明,用背散射法测得金的溅射率与G.K.Wehner用称重法测定的数据很接近,其与入射离子能量的关系为Y∝E~(0.4)。     

聚焦重离子束溅射制备同位素靶的材料利用率及均匀性研究

研究了聚焦重离子束溅射制备同位素靶的材料利用率和均匀性。通过实验确定了两种溅射距离(7 mm和14 mm)下沉积靶的纵向和横向厚度分布,确定了提高靶均匀性的有效方法——基衬公转和沉积1/2厚度后基衬调头,确定了匹配材料利用率和均匀性的最佳几何参数。制备了5种同位素氧化物靶和9种高熔点金属同位素靶,应用于核物理测量实验。实验表明,源-衬距离为7 mm和14 mm时,在9 mm×10 mm成膜区域内,基衬中心距靶(源)材料水平界面垂直距离为9 mm和11 mm时可获得均匀的靶膜和最高的材料利用率。     

90°散射角下源激发X射线荧光测量的最佳入射角及源-靶-探测器结构的改进

在90°散射角下,从基本激发方程出发,导出了以基体对入射与出射X射线质量吸收系数比为变量的最佳入射角表达式。按所求最佳入射角设计源-靶-探测器结构,使厚靶的低能端X射线射出介面的强度增强约20％,而且由于出射角减小,缩短了靶-探测器距离,从而使全谱探测效率提高20％左右。采用椭圆锥面准直孔、并将口部削成适当角度,可显著减小散射本底。     

100keV Ar~+、Ne~+轰击铜靶所产生的溅射原子角分布与离子入射角的关系

在40°和70°斜入射条件下,用100keV Ar~+、Ne~+轰击铜靶,Ar~+所产生的溅射原子角分布的溅射优先方向分别位于表面法线的两侧,溅射原子角分布对于表面法线明显不对称;而Ne~+所对应的溅射优先方向都位于表面法线方向,且溅射原子角分布对于表面法线是对称的。用级联碰撞理论分析了所得到的实验结果,并比较了Ar~+和Ne~+溅射机制上的不同。     

Ar离子轰击Ag靶的溅射角分布

本文描述了用溅射粒子捕集器和Rutherford背散射分析测定溅射粒子角分布的实验方法。给出了100keV Ar~+在入射角分别为0°、30°、50°和80°时轰击Ag靶的溅射角分布。角分布偏离余弦形状,有前倾趋势。溅射产额随入射角增大而迅速增加。由50keV Ar~+垂直入射Ag的溅射角分布计算出的总溅射产额为16.8±2.4~(atoms)/Ar~+。实验结果与理论值进行了比较,并作了定性分析。     

离子法向轰击单元素靶溅射产额的解析估算

给出了计算离子法向轰击单元素靶溅射产额的通用解析公式，将该解析公式估算值、蒙特卡罗模拟值与相应实验数据进行了比较，并用Ｗｉｌｃｏｘｏｎ配对符秩检验法研究了上述结果的显著性差异。     

软X射线激光用分束镜研究

软X射线干涉测量是通过软X射线激光经过马赫-詹德干涉仪完成的，是测量驱动激光临界面附近等离子体状态的重要方法。本基于软X射线多层膜的性能特点，指出软X射线干涉测量的干涉仪各光学元件的入射角越接近正入射越好，分束镜的设计应以其反射率和透过率的乘积为衡量标准。用离子束溅射法制作了类镍银13．9nm软X射线激光干涉测量所需的分束镜，实测表明其面形精度达到纳米量级，反射率和透过率乘积大于1．6％。     

Total sputtering yields of solids under MeV-energy Si ion bombardment

Total sputtering yields have been measured for SiO₂ and Cu targets bombarded with Si ions at an incident energy between 500 keV and 5.0 MeV using a quartz crystal microbalance technique. In order to measure total yields accurately, we have developed a beam modulation technique to avoid the effect of thermal drift. In the MeV energy range, an ion penetrates through thin SiO₂ and Cu targets and is implanted into a quartz crystal. Therefore, the thickness of these layers deposited on quartz crystals was carefully controlled to avoid damage of quartz crystal by incident ions. As a result, total sputtering yields of SiO₂ increased with incident Si ion energy, while those of the Cu target decreased. The total yields of the SiO₂ target were represented well by a power low of the electronic stopping power.     

高剂量注入中离子溅射的影响

在离子注入材料改性的研究过程中(金属、绝缘材料和光学材料等),在许多场合下,要求注入的元素(如Fe中注入N、Y、Ph和Sn等)在靶子中占百分之几的含量,这就要求注入剂量高达10~(17)/cm~2到10~(12)/cm~2。由于离子注入的溅射效应在低能和大剂量注入中是相当明显的,因此,对这些元素高剂量注入后的杂质分布、溅射系数、溅射厚度和靶子中杂质的收集量做一分析是十分重要的。     

A Monte Carlo study of surface sputtering by dual and rotated ion beams

Several, recently proposed methods of surface manufacturing based on ion beam sputtering, which involve dual beam setups, sequential application of ion beams from different directions, or sample rotation, are studied with the method of kinetic Monte Carlo simulation of ion-beam erosion and surface diffusion. In this work, we only consider erosion dominated situations. The results are discussed by comparing them to a number of theoretical propositions and to experimental findings. Two ion-beams aligned opposite to each other produce stationary, symmetric ripples. Two ion beams crossing at right angle will produce square patterns only, if they are exactly balanced. In all other cases of crossed beams, ripple patterns are created, and their orientations are shown to be predictable from linear continuum theory. In sequential ion-beam sputtering we find a very rapid destruction of structures created from the previous beam direction after a rotation step, which leads to a transient decrease of overall roughness. Superpositions of patterns from several rotation steps are difficult to obtain, as they exist only in very short time windows. In setups with a single beam directed towards a rotating sample, we find a non-monotonic dependence of roughness on rotation frequency, with a very pronounced minimum appearing at the frequency scale set by the relaxation of prestructures observed in sequential ion-beam setups. Furthermore we find that the logarithm of the height of structures decreases proportional to the inverse frequency.     

Interaction of fast hydrogen ions with silicon surface at glancing angles of incidence

Angular distributions of 380 keV protons reflected from (1 1 1) surface of Si monocrystal were measured in the range of projectiles glancing angle from 0.3° up to 0.8°. It is shown that increase of glancing angle causes non-linear change of such distribution parameters as angular width of the front rise, angular width of the distribution, the maximum yield value. Registered energy spectrum of reflected particles for glancing angle of 0.5° consists of several peaks with practically constant angular intervals between them and maxima weakly reducing towards lower energy region. It is experimentally shown that the most energetic peak relates to the reflection from the very surface and the rest ones are caused by successive scattering of ions by inner silicon crystallographic planes.     

GCr15表面钽沉积及碳离子注入的摩擦性能的研究

GCr15钢广泛用于各类轴承制造.为提高其摩擦性能,用磁控溅射法在GCr15轴承钢试样表面沉积厚约100 nm的钽膜,再进行不同注量的50 keV碳离子注入.用Ф6的GCr15钢球做对磨试验,测试它们的摩擦性能,用SEM观察磨痕形貌.结果表明,处理后GCr15钢改性层的Ta2C含量随注量增加,摩擦性能得以提高.载荷1 N、滑动速度50 mm/s条件下,注入3×1017ions/cm2的试样耐磨性是原始试样的1.65倍;表面沉积钽膜后,摩擦系数由未处理前的0.8～1下降至0.5左右,钽膜注碳后摩擦系数更降至0.2～0.3,注入层主要以磨粒磨损为主.     

860 A溅射负离子源电离器及电源的改进

本文采用直径为2.5 mm的不锈钢铠装热丝研制了透射型表面电离器,并对离子源电源进行了改进。用连续可调直流开关电源代替原装交流电源作为电离器电源,用置于地电位的0~-20 kV电源代替原悬浮于-20 kV引出电压上的10 kV浸没透镜电源。给出了改进后GIC4117 2×1.7 MV串列加速器前法拉第杯H^-流强随电离器加热电流的变化曲线。     

碳离子束对甜高梁辐射诱变的当代效应

利用兰州重离子加速器提供的中能碳离子束对甜高高粱品种BJ0601和BJ0602进行了不同剂量的辐照处理，以期选育出生物学产量高、汁液糖锤度高及抗逆性强的品种。当代田间试验结果表明：（1）甜高梁在田间的存活曲线均呈“类马鞍型”，随着剂量的增加，其存活率先降后升再下降；（2）随着辐照剂量的变化，其茎秆亩产量、糖锤度和对照相比，均发生了明显的变化；（3）经过碳离子束辐照，出现了株高、单秆重、糖锤度高、早熟、茎粗等突变类型，为进一步的品种选育和诱变机理研究奠定基础。     

New Method of Large-Area DC Ion Beam Formation with Multiple Electron Beams, (II)

A new method to form a small divergence dc ion beam using a large-area single-hole electrode instead of a multiaperture electrode is described. A distinctive feature of this method is to make use of multiple electron beams in an ion source to control the spatial ion density distribution at the region of ion beam formation; the electron beams play a role to aid formation of the concave plasma boundary, which is required to extract a convergent ion beam from gaseous plasma according to the experimental facts described in Part (I). In this experiment, it was verified with three slab-like electron beams that formation of the concave boundary was possible in a stable and steady state. This electrode system can be applied to some types of the present high current ion sources to obtain large-area dc ion beams.