Anomalous scaling in surface roughness evaluation of electrodeposited nanocrystalline Pt thin films

Atomic force microscopy (AFM) is used to measure the surface roughness of crystalline Pt thin films as a function of film thickness and growth rate. Our films were electrodeposited on Au/Cr/glass substrates, under galvanostatic control (constant current density), from a single electrolyte containing Pt⁴⁺ ions. Crystalline structure of the films was confirmed by X-ray diffraction (XRD) technique. The effect of growth rate (deposition current density) and film thickness (deposition time) on the kinetic roughening of the films were studied using AFM and roughness calculation. The data is consistent with a rather complex behaviour known as “anomalous scaling” where both local and large scale roughnesses show power law dependence on the film thickness.     

Surface fission tracks in diamond

Scanning Probe Microscope (SPM) images reveal important fingerprint features of latent tracks induced in diamond by fission fragments from a californium source. Collimated fission fragments with a binary distribution of the predominant energies of 79.4 and 103.8 MeV, are assumed. Cavities, reticular formations around these cavities, and black spots of graphite were found. A brief discussion on the possible track formation mechanism is given on the basis of the explosion spike theory; an attempt to determine latent track core and halo parameters is included.     

Investigation of interface roughness cross-correlation properties of optical thin films from total scattering losses

The interface roughness and interface roughness cross-correlation properties affect the scattering losses of high-quality optical thin films. In this paper, the theoretical models of light scattering induced by surface and interface roughness of optical thin films are concisely presented. Furthermore, influence of interface roughness cross-correlation properties to light scattering is analyzed by total scattering losses. Moreover, single-layer TiO₂ thin film thickness, substrate roughness of K9 glass and ion beam assisted deposition (IBAD) technique effect on interface roughness cross-correlation properties are studied by experiments, respectively. A 17-layer dielectric quarter-wave high reflection multilayer is analyzed by total scattering losses. The results show that the interface roughness cross-correlation properties depend on TiO₂ thin film thickness, substrate roughness and deposition technique. The interface roughness cross-correlation properties decrease with the increase of film thickness or the decrease of substrates roughness. Furthermore, ion beam assisted deposition technique can increase the interface roughness cross-correlation properties of optical thin films. The measured total scattering losses of 17-layer dielectric quarter-wave high reflection multilayer deposited with IBAD indicate that completely correlated interface model can be observed, when substrate roughness is about 2.84 nm.     

Surface cleaning procedures for thin films of indium gallium nitride grown on sapphire

Surface preparation procedures for indium gallium nitride (InGaN) thin films were analyzed for their effectiveness for carbon and oxide removal as well as for the resulting surface roughness. Aqua regia (3:1 mixture of concentrated hydrochloric acid and concentrated nitric acid, AR), hydrofluoric acid (HF), hydrochloric acid (HCl), piranha solution (1:1 mixture of sulfuric acid and 30% H₂O₂) and 1:9 ammonium sulfide:tert-butanol were all used along with high temperature anneals to remove surface contamination. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were utilized to study the extent of surface contamination and surface roughness, respectively. The ammonium sulfide treatment provided the best overall removal of oxygen and carbon. Annealing over 700 °C after a treatment showed an even further improvement in surface contamination removal. The piranha treatment resulted in the lowest residual carbon, while the ammonium sulfide treatment leads to the lowest residual oxygen. AFM data showed that all the treatments decreased the surface roughness (with respect to as-grown specimens) with HCl, HF, (NH₄)₂S and RCA procedures giving the best RMS values (∼0.5-0.8 nm).     

Regeneration of surface roughness by the Langevin equation using stochastic analysis on AFM image of a carbon fiber

A new method was developed using AFM images of a fiber surface to regenerate the surface roughness in 3D geometry, such as the cylindrical shape of a “model” fiber. The Langevin equation was used to derive the fluctuations of a carbon fiber surface image. The equation contains two quantities, D⁽¹⁾ (h) and D⁽²⁾ (h) which in physics represent drift and diffusion coefficients. Knowing this coefficient and adding a proper noise function, a similar surface of larger dimension with the same statistical properties of the initial data was created. The generated surface was mapped into cylindrical coordinates, then a mesh generated. The resulting reconstructed surface, input over the geometry of a cylindrical shape, can be implemented for finite element analysis of a single fiber surrounded by matrix and generalized to a many fiber model.     

磁控溅射制备Ni/Ti多层膜表面粗糙度

采用磁控溅射方法制备了周期数分别为10,30,50和75的Ni/Ti多层膜,利用X射线掠入射反射测量了多层膜表面和界面的状态,并用原子力显微镜测量了多层膜的表面粗糙度,研究了不同周期数的Ni/Ti多层膜表面粗糙度的变化规律。结果表明:Ni/Ti多层膜表面粗糙度随着膜层数增加而增加,当Ni/Ti多层膜的周期数从10变化到75时,其表面粗糙度由0.80 nm增大到1.69 nm。实验数据拟合表明:Ni/Ti多层膜表面粗糙度与周期数成3次方关系;但在周期数较小时,粗糙度与周期数成线性关系。     

Experimental investigation of a modified Beckmann-Kirchhoff scattering theory for the in-process optical measurement of surface quality

An experimental investigation of a modified Beckmann-Kirchhoff scattering theory applied in an in-process optical measurement of surface quality is described. The proposed theory describes the scattered light intensity distribution from a surface with the additional layers, and can be employed to analyze the surface characteristics in in-process measurement. Based on light scattering principle and machine vision method, the surface roughness is extracted to testify the correction of the modified Beckmann-Kirchhoff scattering theory. The experimental apparatus consists of a collimated laser diode, a beam splitter, a screen, a measuring lens and a camera. Test specimens with different surface roughness are studied. The results obtained demonstrate the feasibility of in-process optical measurement of surface quality using the modified model.     

Track sensitivity and the surface roughness measurements of CR-39 with atomic force microscope

Atomic Force Microscope (AFM) has been applied to evaluate the surface roughness and the track sensitivity of CR-39 track detector. We experimentally confirmed the inverse correlation between the track sensitivity and the roughness of the detector surface after etching. The surface of CR-39 (CR-39 doped with antioxidant (HARZLAS (TD-1)) and copolymer of CR-39/NIPAAm (TNF-1)) with high sensitivity becomes rough by the etching, while the pure CR-39 (BARYOTRAK) with low sensitivity keeps its original surface clarity even for the long etching.     

高光洁度玻璃基片的表面散射和体散射测量

 提出了一种利用总积分散射（TIS）测量K9玻璃基片表面散射和体散射的实验方法。首先采用磁控溅射技术在基片表面沉积厚度为几十nm的金属Ag薄膜,然后将基片的表面和体区分开考虑,通过TIS测得了基片上下表面的均方根粗糙度, 进而求得基片的总散射和表面散射,最后计算得到了体散射。分别利用TIS和原子力显微镜（AFM）测量了3个样品上表面所镀Ag膜的均方根粗糙度,两种方法所得的均方根粗糙度的数值相差不明显,差值分别为0.08,0.11和0.09 nm, 表明TIS和AFM的测量结果相一致。利用该方法测得3块K9玻璃基片的总散射分别为6.06×10^-4,5.84×10^-4和6.48×10^-4,表面散射介于1.25×10^-4~1.56×10^-4之间,由此计算得到的体散射分别为3.10×10^-4,3.30×10^-4和3.61×10^-4。     

磁控溅射制备Ni/Ti多层膜表面粗糙度

采用磁控溅射方法制备了周期数分别为10,30,50和75的Ni/Ti多层膜,利用X射线掠入射反射测量了多层膜表面和界面的状态,并用原子力显微镜测量了多层膜的表面粗糙度,研究了不同周期数的Ni/Ti多层膜表面粗糙度的变化规律。结果表明：Ni/Ti多层膜表面粗糙度随着膜层数增加而增加,当Ni/Ti多层膜的周期数从10变化到75时,其表面粗糙度由0.80 nm增大到1.69 nm。实验数据拟合表明：Ni/Ti多层膜表面粗糙度与周期数成3次方关系;但在周期数较小时,粗糙度与周期数成线性关系。     

AFM observations of latent fission tracks on surfaces: amorphous SiO2 and quartz

Preliminary results of a systematic AFM experimental investigation of the surface ‘track’ effects produced by the passage of fission fragments from a californium (²⁵²Cf) source into amorphous SiO₂ and quartz are described. Fission fragments from the source were collimated using a 10 μm thick aluminum foil and comprised fragments with the usual binary distribution of energies—light and heavy—79.4 and 103.8 MeV. Irradiations and AFM measurements were carried out in air at normal room temperature and pressure. Remarkably high sputtering yields/fragment were discovered, and in the case of crystalline quartz the ejecta was found to be arranged in an ordered manner. A brief discussion is given of a part likely to be played by electronic energy loss induced Coulomb explosion of target atoms for each point of fragment entry.     

神经节苷脂的红外、紫外光谱分析及其多聚体结构的原子力显微镜观测

神经节苷脂(gangliosides, Gls)是一类含有唾液酸的酸性鞘糖脂,是神经细胞膜的重要组成成分,在生物膜中起着非常重要的生理作用。文章用红外光谱(IR)、紫外光谱(UV)、原子力显微镜(AFM)分别对以牛脑为原料,采用Folch萃取法、硅胶吸附柱层析和DEAE-SephadexA-25离子交换柱层析得到的神经节苷脂的分子官能团和多聚体结构进行了研究。实验结果表明,从100 g湿组织中获得产品为55.2 mg,纯度达62.84%,其紫外光谱吸收在195 nm处。通过红外光谱研究证明在提纯的产品结构中含有唾液酸分子的结构片段。利用原子力显微镜对其在水中的聚集体微观形貌进行了观察研究,发现神经节苷脂在水中呈清晰的纳米级球状或椭球状结构,经测定：神经节苷脂多聚体的大小在55～380 nm之间,平均大小为(148.9±66.7) nm;高度在1.0～5.0 nm之间,平均高度为(3.25±1.01) nm。该实验结果为神经节苷脂的生物活性研究以及作为神经类药物的开发利用提供了理论和实验依据。     

A study of the transient current during the formation of titanium oxide nanodots by AFM anodic oxidation

We analyze transient current data during the formation of titanium oxide nanodots by AFM-tip-induced anodic oxidation with the aim of getting further understanding of local oxidation kinetics. The measured current waveforms show a transition between two distinct regimes, in agreement to what was previously known of the growth process, and their behavior is discussed with respect to the oxide growth rate and to the formation of the space charge. Furthermore, it is shown how the knowledge of the duration of the first transient regime can be exploited to optimize the application of pulsed bias voltages to obtain a substantial improvement in aspect ratio of growing oxides.     

Characterization of post-copper CMP surfaces with scanning probe microscopy: Part 1: Surface leakage measurement with conductive atomic force microscopy

We demonstrate in this paper for the first time the use of conductive atomic force microscopy (AFM) to measure surface leakage between copper structures with varying line width and spacing in the micro and sub micrometer ranges. Conducting atomic force microscopy allows subsequent measurement of the topography as well as the electrical properties of surfaces. The feasibility and interest of these measurements will be shown by studying the impact of chemical mechanical polishing (CMP) of an electrical interface bearing different micrometric copper structures. As expected the polishing time has a crucial impact on the current determined between closely spaced copper structures. This paper will also deal with issues observed during the measurement.     

Fractal analysis and atomic force microscopy measurements of surface roughness for Hastelloy C276 substrates and amorphous alumina buffer layers in coated conductors

In coated conductors, surface roughness of metallic substrates and buffer layers could significantly affect the texture of subsequently deposited buffer layers and the critical current density of superconductor layer. Atomic force microscopy (AFM) is usually utilized to measure surface roughness. However, the roughness values are actually relevant to scan scale. Fractal geometry could be exerted to analyze the scaling performance of surface roughness. In this study, four samples were prepared, which were electro polished Hastelloy C276 substrate, mechanically polished Hastelloy C276 substrate and the amorphous alumina buffer layers deposited on both the substrates by ion beam deposition. The surface roughness, described by root mean squared (RMS) and arithmetic average (R_a) values, was analyzed considering the scan scale of AFM measurements. The surfaces of amorphous alumina layers were found to be fractal in nature because of the scaling performance of roughness, while the surfaces of Hastelloy substrates were not. The flatten modification of AFM images was discussed. And the calculation of surface roughness in smaller parts divided from the whole AFM images was studied, compared with the results of actual AFM measurements of the same scan scales.     

Effects of parylene C layer on high power light emitting diodes

20 μm parylene C layer was deposited on silicone film to enhance the oxygen and water barrier properties, deposited at typical rate of 2.0 and 5.6 μm/h by controlling different deposited pressures. Surface morphology and roughness were observed by atomic force microscopy (AFM), surface morphology images show lower deposited rate that can lead to better quality film. 20 μm parylene C layer was deposited on silicone encapsulation of high power light emitting diodes (LEDs), the samples were tested by power temperature cycling (PTC) test from −40 to 85 °C, 15 min each extreme, and no corrosion, discoloration, cracks was found on the LEDs after the 1000 h PTC reliability test, and PTC test is intended to simulate worst case conditions encountered in typical applications, and parylene C floating membrane structure can stand such high stress and strain. Optical test on white and red LED samples with and without 20 μm parylene C layer, measurement result shows the optical transmittance more than 95%. 1000 h temperature humidity bias life test (T&HB) is performed for the purpose of evaluating the reliability of LEDs in humid environments, energy-dispersive X-ray (EDX) analysis revealed much lower content of C (carbon) and O (oxygen) on the lead frame of LED with parylene C coating after T&HB test on, and no oxidation was found in the LED package.     

Surface roughness characterization of Al-doped zinc oxide thin films using rapid optical measurement

Transparent conductive oxide thin films have been widely investigated in photoelectric devices such as flat panel display (FPD) and solar cells. Al-doped zinc oxide (AZO) thin films have been widely employed in FPD. Measuring the surface roughness of AZO thin films is important before the manufacturing of photoelectric device using AZO thin films because surface roughness of AZO thin films will significantly affect the performance of photoelectric device. Traditional methods to measure surface roughness of AZO thin films are scanning electron microscopy and atomic force microscopy. The disadvantages of these approaches include long lead time and slow measurement speed. To solve this problem, an optical inspection system for rapid measurement of the surface roughness of AZO thin films is developed in this study. It is found that the incident angle of 60° is a good candidate to measure the surface roughness of AZO thin films. Based on the trend equation y=−3.6483x+2.1409, the surface roughness of AZO thin films (y) can be directly deduced from the peak power density (x) using the optical inspection system developed. The maximum measurement-error rate of the optical inspection system developed is less than 8.7%.The saving in inspection time of the surface roughness of AZO thin films is up to 83%.     

Live morphological analysis of taxol-induced cytoplasmic vacuolization [corrected] in human lung adenocarcinoma cells

Taxol (paclitaxel), one of the most active cancer chemotherapeutic agents, can cause programmed cell death (PCD) and cytoplasmic vacuolization. The objective of this study was to analyze the morphological characteristics induced by taxol. Human lung adenocarcinoma (ASTC-a-1) cells were exposed to various concentration of taxol. CCK-8 was used to assay the cell viability. Atomic force microscopy (AFM), plasmid transfection and confocal fluorescence microscopy were performed to image the cells morphological change induced by taxol. Fluorescence resonance energy transfer (FRET) was used to monitor the caspase-3 activation in living cells during taxol-induced cell death. Cells treated with taxol exhibited significant swelling and cytoplasmic vacuolization which may be due to endoplasmic reticulum (ER) vacuolization. Caspase-3 was not activated during taxol-induced cytoplasmic vacuolization and cell death. These findings suggest that taxol induces caspase-3-independent cytoplasmic vacuolization, cell swelling and cell death through ER vacuolization.