准分子激光电化学刻蚀金属的研究

为了探寻准分子激光电化学刻蚀工艺的特性,采用功率密度大的248nm准分子激光聚焦照射浸在溶液中的金属表面,实现了一种激光电化学刻蚀复合工艺。在实验的基础上,通过对激光电化学刻蚀金属和硅的基本形貌进行比较和分析,研究了该工艺的工艺特性。研究结果表明,该复合工艺为激光直接刻蚀和激光热诱导电化学刻蚀。其中激光热诱导电化学刻蚀是通过激光的光热效应和由激光诱导的冲击波来实现对腐蚀液和材料的冲击、微搅拌等作用的。     

308nm准分子激光对C60薄膜的刻蚀特性研究

测量在空气和真空中３０８ｎｍ准分子激光对Ｃ６０薄膜的刻蚀速率和刻蚀阈值，讨论了环境中氧气对刻蚀特性的影响。     

脉冲激光与电化学复合的应力刻蚀加工质量研究

脉冲激光电化学复合加工可以有效去除激光辐照区域内的电解产物, 提高加工效率, 改善加工质量. 针对高性能金属材料的微细加工要求, 采用脉冲激光电化学复合的应力刻蚀加工方法对铝合金的刻蚀特性进行理论和试验研究. 通过比较激光直接刻蚀加工和激光电化学复合加工的特点, 应用扫描电子显微镜、光学轮廓仪等检测技术分析了刻蚀区域的形貌特征. 根据力学电化学原理, 探讨了金属材料微结构加工的应力去除机理. 通过加工试验, 研究了工艺参数和加工方式对加工质量的影响, 采用优化的工艺参数, 加工出了质量较好的微结构. 试验结果表明, 激光电化学复合的连续扫描加工稳定性好, 可以有效地降低表面粗糙度, 提高加工质量. 关键词： 激光电化学 应力刻蚀 加工质量 工艺参数     

C60薄膜的准分子激光刻蚀及形貌分析

报道了准分子ＸｅＣｌ（３０８ｎｍ）紫外激光刻蚀Ｃ６０膜的实验研究及对刻蚀薄膜的形貌分析。基于形貌分析的结果提出其刻蚀机理。     

短谐振腔准分子激光输出的脉冲特性研究

用腔长为7.5cm～20cm的紫外光预电离Blumlein横向放电泵浦XeCl准分子激光器可产生半宽为1.8ns～5ns的短脉冲输出。速率方程的计算机模拟所给出的激光振荡初始尖峰和实验结果做了比较。     

紫外准分子激光损伤典型光学材料的特性分析

根据已经建立的紫外准分子激光损伤典型光学材料的理论模型,研究了准分子激光对透明光学材料（石英玻璃）和非透明光学材料（K9玻璃）的损伤特性,并结合实验结果证实了理论模型的有效性。研究表明：在准分子激光对非透明光学材料辐照下,激光光斑半径越大,产生的热应力和温度越小;脉宽越小,产生的热应力越大;随着脉冲数的增加,温度和热应力都逐渐增大。值得注意的是,当重频增加至45 Hz以上时,熔融损伤阈值开始低于应力损伤阈值,这说明当重频增加到一定程度时,非透明光学材料将首先产生熔融损伤,而不再是应力损伤。在准分子激光对透明光学材料辐照下,杂质微粒的半径和掩埋深度对光学材料温度场分布有着重要影响。但当杂质半径和掩埋深度超过一定的数值时,杂质粒子的存在与表面温度并无联系。理论模型能够较好地解释石英玻璃前/后表面相同的初始损伤形貌特征。     

ArF准分子激光振荡放大系统的研究

研究了ＡｒＦ准分子激光振荡放大系统，中心波长１９３ｎｍ，用一只闸流管作为开关元件，通过主充放电网络匹配，有效地解决了两台器件的放电抖动，振荡放在倍数达到约５０倍，系统单脉冲输出能量５０ｍＪ，光束发射角低于０．２０ｍｒａｄ。     

XeCl准分子激光光束均匀器及其应用

采用光束均匀器，改善ＸｅＣｌ准分子激光器输出光束强度的分布，其起伏优于２％，用这一装置测量了Ｃ６０薄膜的刻蚀阈值，并完成了准分子激光改变Ｃ６０薄膜电导率的实验研究。     

准分子激光拉曼种子源

对准分子激光拉曼种子源进行了深入研究。采用波导型拉曼地增强拉曼转换，并在氢气中掺入一定比分的氦气来控制向各阶斯托克斯光的能量转换。当无掺杂时，获得一阶斯托克斯光的最大转换效率η＿（ｍａｘ）＝３７％。当在氢气中掺入氦气比分为５％时，在泵浦能量范围５０～８０ｍＪ内获得一阶高转换效率（η＇≥９５％η＿（ｍａｘ）），二阶及高阶斯托克斯光的转换受到抑制。对实验结果进行了理论分析。     

Directly heated etching stand for electrochemical treatment of track detectors

The directly electrically heated etching stand has been developed for the electrochemical treatment of track detectors to avoid the time consuming overnight pre-heating and to simplify the procedure. The large plate electrode containing several heating elements on its rear side creates the main part of the etching stand. The temperature of the electrode connected to the control unit is variable within 30–70°C. Two types of etching stands were tested. The uniformity of the temperature distribution on the electrode surface, heating rate and stability of temperature were studied as the main parameters and the results are presented. The technical solution allows to construct smaller (even portable) devices for the electrochemical etching.     

熔石英元件HF刻蚀的实验研究

为深入了解熔石英元件化学刻蚀过程,研究了HF刻蚀反应机理、HF刻蚀工艺参数以及刻蚀对表面质量的影响规律。通过控制变量法,获得刻蚀速率随HF浓度、刻蚀温度以及NH4F浓度的变化规律。对刻蚀不同深度后的元件表面粗糙度、形貌、杂质含量以及激光损伤阈值进行了检测,实验结果表明：刻蚀速率受多种因素共同影响,其中HF浓度的促进作用最为显著;刻蚀后的熔石英表面形貌复杂,有横向、纵向、拖尾等形式的划痕,以及坑点、杂质等缺陷,其中横向划痕和纵向划痕占据了缺陷部分的主体,主要杂质铈元素随刻蚀时间的增长不断减少;激光损伤阈值测量实验表明,通过HF刻蚀将元件损伤阈值提高了59.6%。     

部分相干源实验研究

 在无阶梯诱导空间非相干光束平滑技术中，用作前端的部分相干源是重要的组成部分。介绍了利用准分子激光进行的部分相干源实验，发现聚四氟乙烯是一种较理想的散射材料。研究了聚四氟乙烯散射源对光束的散射性能，给出了光束均匀性、空间相干性和能量转换效率等参数。     

离子束刻蚀技术研究

本文介绍了离子束刻蚀技术的原理,讨论了刻蚀速率与离子束流密度、离子能量和离子束入射角度的关系。实验结果与理论分析有较好的一致性。     

The study of the solution concentration influencing on laser-induced electrochemical etching silicon

The laser electrochemical etching process, which combines the laser direct etching process and the electrochemical etching process, is a compound etching technique. In order to further understand the solution concentration influencing on the laser-induced electrochemical etching of silicon; a 248 nm excimer laser as a light source and KOH solution as an electrolyte were adopted in this study. The experiments of micromachining silicon by laser-induced electrochemical etching were carried out. On the basis of the experiments results, the solution concentration influencing on the etching rates in the process of laser electrochemical etching of silicon was researched. The reasons of the etching phenomena were analyzed in detail. The experimental results indicate that the solution concentration influencing on the etching process is mainly rooted in the absorption of different concentration solutions to laser. In general, less absorption and low solution concentration are good for the etching role in the process of laser electrochemical etching.     

Preparation of a nanopatterned surface of bonded silicon wafers using electrochemical thinning and chemical etching: A scanning tunnel microscopy investigation

Sacrificial anodic oxidation is used to thin silicon wafer bonding substrates. Chemical solutions, sensitive to the periodic strain field present in the upper ultra-thin silicon layer, are employed for selective etching. Subsequent scanning tunnel microscopy observations reveal a square array of trenches corresponding to the buried screw dislocation network initially formed at the bonding interface. The influence of the initial thickness and the annealing of the ultra-thin film on roughness and trench depth of the nanopatterned substrates are examined. Germanium growth experiments are performed in order to show the self-organization character of resulting structured surfaces.     

Stiffness properties of porous silicon nanowires fabricated by electrochemical and laser-induced etching

Nanowires with dimensions of few nanometers were formed on the whole etched surface. The optical analysis of silicon nanostructures was studied. Blue shift luminescence was observed at 660 nm for PS produced by electrochemical etching, and at 629 nm for laser-induced etching. PS produced a blue shift at 622 nm using both etching procedures simultaneously. X-ray diffraction (XRD) was used to investigate the crystallites size of PS as well as to provide an estimate of the degree of crystallinty of the etched sample. Refractive index, optical dielectric constant, bulk modulus and elasticity are calculated to investigate the optical and stiffness properties of PS nanowires, respectively. The elastic constants and the short-range force constants of PS are investigated.     

Comparing study of subpicosecond and nanosecond wet etching of fused silica

The effectiveness of the laser induced backside wet etching (LIBWE) of fused silica produced by subpicosecond (600 fs) and nanosecond (30 ns) KrF excimer laser pulses (248 nm) was studied. Fused silica plates were the transparent targets, and naphthalene-methyl-methacrylate (c = 0.85, 1.71 M) and pyrene-acetone (c = 0.4 M) solutions were used as liquid absorbents. We did not observe etching using 600 fs laser pulses, in contrast with the experiments at 30 ns, where etched holes were found. The threshold fluences of the LIBWE at nanosecond pulses were found to be in the range of 360-450 mJ cm⁻² depending on the liquid absorbers and their concentrations. On the basis of the earlier results the LIBWE procedure can be explain by the thermal heating of the quartz target and the high-pressure bubble formation in the liquid. According to the theories, these bubbles hit and damage the fused silica surface. The pressure on the irradiated quartz can be derived from the snapshots of the originating and expanding bubbles recorded by fast photographic setup. We found that the bubble pressure at 460 mJ cm⁻² fluence value was independent of the pulse duration (600 fs and 30 ns) using pyrene-acetone solution, while using naphthalene-methyl-methacrylate solutions this pressure was 4, 5 times higher at 30 ns pulses than it was at 600 fs pulses. According to the earlier studies, this result refers to that the pressure should be sufficiently high to remove a thin layer from the quartz surface using pyrene-acetone solution. These facts show that the thermal and chemical phenomena in addition to the mechanical effects also play important role in the LIBWE procedure.     

酸蚀与紫外激光预处理结合提高熔石英损伤阈值

采用HF酸刻蚀和紫外激光预处理相结合的方式提升熔石英元件的负载能力,用质量分数为1%的HF缓冲溶液对熔石英刻蚀1~100 min,综合透过率、粗糙度和损伤阈值测试结果,发现刻蚀时间为10 min的熔石英抗损伤能力最佳。采用355 nm紫外激光对HF酸刻蚀10 min的熔石英进行预处理,结果表明：紫外预处理能量密度在熔石英零损伤阈值的60%以下时,激光损伤阈值单调递增;能量到达80%时,阈值反而低于原始样片的损伤阈值。适当地控制酸蚀时间和紫外激光预处理参数能有效提高熔石英的抗损伤能力。