高速原子力显微术研究进展

自1986年发明原子力显微镜以来,它已成为材料、生物以及纳米科技等许多领域的重要工具。由于常规原子力显微镜成像速度缓慢,在动态过程观测、工业生产线原位测量以及高密度信息存储等领域的应用受到限制,因此发展高速原子力显微术近年来已引起国内外的高度关注。本文综述了高速原子力显微术关键技术(包括:微小探针、高速扫描器设计和控制方法)以及应用等方面的最近进展。     

On simulation of resist profiles in electron beam lithography

Resist profiles in electron beam exposed PMMA have been simulated before and after proximity exposure compensation (correction) for isolated and closely spaced line patterns. Edge slope of the resist profiles obtained in the two cases (before and after proximity exposure compensation) indicate the effectiveness of the compensation technique. Along with the edge slopes the line width variations are also determined.     

Thermal detection of device failure by atomic force microscopy

Device and interconnect electrical failures often occur in the form of short or open circuits which produce hot or cold spots under voltage bias. With the minimum device feature size shrinking to 0.25 μm and less, it is impossible to locate the exact position of defects by traditional thermal or optical techniques such as infra-red emission thermometry, liquid crystals or optical beam induced current. We have used a temperature-sensing probe in an atomic force microscope to locate a hot spot created by a short-circuit defect between the gate and the drain of a Si MOSFET with a spatial resolution of about 0.5 μm. The technique has the potential to produce spatial resolutions in the range of 0.05 μm and efforts are underway to reach this goal     

Local oxidation of titanium films by non-contact atomic force microscopy

Characteristics of local nanolithography on oxidative titanium dots and wires were studied using an amplitude modulation atomic force microscopy in the non-contact mode. Nanolithographic experiments were conducted to investigate the influence that different experimental parameters had on the height, the width, the growth rate, the morphology, and the composition of the nanostructures using Auger electron spectroscopy. The results indicate that anodization time, applied voltage, and tip-sample distance are proportional to the heights and widths of the dots. When the tip-sample distance was too close during continued anodization, concave dots appeared because the oxide that enclosed the tip. Carbon nanotube probe fabricated dots are also presented and compared.     

原子力显微镜激光光路调整方法

ＣＳＰＭ 930ｂ型多功能扫描探针显微镜经常需要进行手动激光光路调整。该仪器使用说明书[1] 介绍的调整方法可操作性差、手续繁琐、过程冗长 ,且难以判断激光束是否准确照射到微悬臂针尖背面的镀金层上 ,往往造成误判而导致微悬臂针尖被撞断裂。而且 ,按照原有方法操作者需要长时间全神贯注观察激光斑 ,使用者眼睛极易疲劳甚至造成损伤。笔者使用该仪器过程中 ,对光路调整方法进行了大量试验 ,摸索出了一套操作方便 ,容易准确判断针尖位置的有效方法。现总结交流如下。调整方法ＣＳＰＭ 930ｂ扫描探针显微镜ＡＦＭ部分激光光路如图 1所示。…     

碳纳米管原子力显微镜针尖的研究

本文研究了制作碳纳米管原子力显微镜针尖的方法和过程。在光学显微镜下,通过两个微工作台操纵将纯化后的多壁碳纳米管粘结在传统的原子力显微镜的Si针尖上。运用电蚀的方法优化碳管针尖的长度使其达到高分辨率的要求。我们运用制作的碳纳米管针尖在敲击模式下时G型免疫球蛋白进行扫描成像,结果显示了其典型的Y形结构,这是传统AFM的Si针尖无法获得的。     

Observations of xenon gas-treated barley cells in solution by atomic force microscopy

Barley cells cut from a sprout were exposed to either air or high-pressure xenon gas for 3 days and the surface of those cells was observed by atomic force microscopy (AFM) to examine the effect of the gas treatment. This method enabled the direct observation of the fresh surface of the barley cells in solution at high resolution. The cuticle layer was preserved on the primary cell wall of 0.48 MPa xenon gas-treated barley cells, while air-treated barley cells lost the cuticle layer from the primary cell wall. These findings indicate that the high-pressure xenon gas treatment is effective to preserve the cuticle layer attached to the primary cell wall. AFM is a powerful tool for the observation of the surface structure of living plant cells in solution.     

纳米颗粒填充的PTFE微结构的原子力显微镜测量

本文报道了用原子力显微镜(AFM)研究多种纳米微粒填充的聚四氟乙烯(PTFE)材料的结构组成,观察了在纳米颗粒填充的PTFE中,纳米微粒的分散不均匀性以及纳米粉末在与PTFE混合、压制后发生的团聚现象。     

利用原子力显微镜鉴别相变诱发塑性钢的显微组织

相变诱发塑性（TRIP）钢比双相钢具有更高强度和塑性，因此TRIP钢在汽车工业中的应用对于汽车轻量化有重要的经济意义。TRIP钢的高强度和高延展性主要来源于钢中复杂的显微组织以及应变条件下亚稳态的残余奥氏体（A1）向马氏全（M）的转变，即相变诱发塑性。钢中各相组织的正确鉴别显得尤为重要，特别是钢中残余奥氏体的含量、分布及其稳定性直接关系到TRIP钢性能的好坏。根据目前使用的常规鉴别方法、     

原子力显微镜对不同条件下果胶微粒的表面形态学观察

果胶是由D-半乳糖醛酸残基经α(1→4)键相连接聚合而成的酸性大分子多糖,并且半乳糖醛酸C6上的羧基有许多是甲酯化形式,根据酯化度DE值可将果胶分为高甲酯果胶(DE值高于50％)和低甲酯果胶(DE值低于50％)。果胶在食品工业中的作用主要表现在增稠、胶凝和稳定。     

乙酰胆碱酯酶分子的原子力显微成像

本文研究了用原子力显微技术对乙酰胆碱酯酶进行成像的方法。在新鲜裂解的云一表面镀一层金膜,金膜与疏基丙酸（ＭＰＡ）的疏基形成Ｓ－Ａｕ键。使ＭＰＡ的游离羧基再通过碳二亚胺反应与ＡＣｈＥ的碱性氨基酸的氨基形成肽键连接,ＡＣｈＥ因而被固定于支持物表面,这样固定的ＡＣｈＥ可获得清晰成像而不脱落。     

In-situ etching observation of human teeth in acid agent by atomic force microscopy

Atomic force microscopy was applied to the in-situ observation of the etching process of human teeth by acid agents. The change of surface morphology was observed consecutively before and during etching for the same area in the same specimen. The course of the etching process in enamel from dissolution of smear layer just after injection of acid agent, appearance of enamel prisms and progress of demineralization were quantitatively analysed for three fundamental acid agents of 2% phosphoric acid, 10% citric acid and 10% polyacrylic acid. Then the depth profile, etching amount, etching rate and thickness of smear layer were evaluated. Observation by scanning electron microscopy was also done and compared with the results by atomic force microscopy.     

基于原子力显微镜技术的单个生物大分子压弹性研究

单个生物大分子力学性质已经成为一个新兴的研究领域,近几年来由于单分子技术的不断发展,这个领域取得了很多突破性的进展。本文介绍了基于原子力显微镜技术的几种单分子压弹性测量技术及这些技术的具体应用,同时也简要阐述了这些技术的局限性。另外对这个领域的发展也进行了初步地探讨。     

AFM反馈系统仿真模型的建立及实验

原子力显微镜（ AFM）广泛应用于纳米尺度的成像和操纵,其较低的扫描速度严重影响了测试的效率。为此,许多研究人员通过设计先进的Z向控制算法改善系统的响应速度,达到提高扫描速度的目的,而先进的控制算法的实现首先需要对AFM的Z向反馈系统进行建模。为此,本文提出一种简单准确的系统辨识方法,通过对系统输入输出数据的分析,得到AFM的Z向反馈系统模型,并利用该模型验证先进控制算法的控制性能。实验表明该方法能为先进控制算法的设计和实现建立有效的仿真模型。     

Improving the sensitivity and line edge roughness in inorganic positive electron beam resist

Need for inorganic electron beam resist with higher sensitivity and resolution is indisputable. We have developed such a resist that also shows lower line edge roughness. It is pre-baked at 300 °C. By using 4 kV EB we have delineated 40 nm lines pattern and honeycomb structure Photonic crystal pattern.     

原子力显微镜相位成像模式的设计及研究

相位成像模式是近几年发展起来的一种原子力显微镜的检测模式,该模式可以提供丰富的样品表面纳米尺度信息,是形貌像的有利补充。本文给出了一种应用原子力显微镜轻敲模式的相位检测电路,结构简单,工作可靠稳定。通过实验获得了一些样品的相位像。     

3 nm NiCr wires made using electron beam lithography and PMMA resist

We demonstrate the fabrication of sub — 5 nm NiCr wires using conventional 100 kV electron beam lithography and PMMA resist technology. The wires are short, and widen to continuous 20 nm wires at either end. The ultra high resolution is achieved using a novel exposure technique. These wires are believed to be the smallest features yet made using this technology.     

AFM的DNA样品制备技术研究

AFM应用中最为关键的一步无疑是样品的制备。本文介绍DNA样品制备的几种主要方法,通过实验发展了两种适合对DNA及其碎片进行长度测量和做统计分析的制样方法,它们分别采用APS-云母和纯云母为衬底。这两种方法不仅丰富了DNA样品制备方法,对推广AFM在生物研究中的应用也具有重要意义。     

Modeling and simulation development of electron beam resist based on cellular automata

This paper presents a robust Cellular Automata model which predicts the two dimensional development profile as a function of development time, exposure dose and electron beam resist type.The main advantage of CA model is that they exhibit high efficiency and accuracy when handling arbitrarily complex system. In the CA method, A resist is represented by an array of discrete cells that reside in a crystalline lattice. Development of the resist is represented by removal and of individual cell according to development rules. During development, the decision to remove or retain a particular cell is based on the link status of its lattice neighbors according to cell-removal rules, The link status is categorized by number of neighboring cells and their relative positions. The modeling approach also uses Monte-Carlo simulation of electron scattering and energy dissipation and a simple development rate versus dose model for the resist. An absolute quantitative evaluation of the simulation accuracy is made based on resist exposure-development measurement and comparisons with SEM micrographs of experimental profiles of PMMA, SAL601 and ZEP520.The comparisons show good quantitative agreement and indicate the model based on CA can be used as a quantitative processing aid. Simulation results illustrate the importance of resist, beam and dose.