Instrument for measuring temperature dependences of characteristics of semiconductor structures

This paper presents an instrument designed to study temperature dependences of the small-signal capacitance and current of semiconductor structures in the range from ?180 to +300 °C.     

Characteristics of cross-sectional atom probe analysis on semiconductor structures

The laser-assisted Atom Probe has been proposed as a metrology tool for next generation semiconductor technologies requiring sub-nm spatial resolution. In order to assess its potential for the analysis of three-dimensional semiconductor structures like FinFETs, we have studied the Atom Probes lateral resolution on a silicon, silicon-germanium multilayer structure. We find that the interactions of the laser with the semiconductor materials in the sample distort the sample surface. This results in transient errors of the measured dimensions of the structure. The deformation of the sample furthermore leads to a degradation of the lateral resolution. In the experiments presented in this paper, the Atom Probe reaches a lateral resolution of 1-1.8 nm/decade. In this paper we will discuss the reasons for the distortions of the tip and demonstrate that with the present state of data reconstruction severe quantification errors limit its applicability for the quantitative analysis of heterogeneous semiconductor structures. Our experiments show that reconstruction algorithms taking into account the time dependent nanostructure of the tip shape are required to arrive at accurate results.     

现代表面分析技术在半导体材料中的应用

本文简要介绍TOF-SIMS(飞行时间二次离子质谱仪)、XRD(X射线双晶衍射仪)、SIMS(二次离子质谱仪)和XPS(X射线光电子能谱仪)等现代分析仪器的特点,着重报道这些分析技术在分析砷化镓抛光片的表面痕量沾污、表面晶体完整性、表面镓砷比、表面化学组成、表面氧含量以及氧化层厚度等方面的应用。     

Determining the heat of a surface plasmochemical reaction by scanning calorimetry

A method for experimental determination of the heat of an exothermic reaction, which proceeds on a solid surface under the action of a chemically active plasma and is accompanied by the production of volatile compounds, is proposed. Scanning calorimetry in a discharge is used in order to determine the contribution due to the heat release of the chemical reaction to the total heat flux onto the surface. It is shown how necessary it is to consider the contributions of different heat exchange mechanisms when determining the reaction heat in the case of a significant difference between the temperatures of the active and inert calorimeters. The heat of the exothermic chemical reaction of atomic fluorine with a unit mass of single-crystal silicon in a CF₄+O₂ plasma is 31±2 kJ/g or 9 eV per Si atom.     

Device for the study of nonequilibrium phenomena in semiconductor structures

A device for studying the relaxation dynamics of nonequilibrium capacitance and charge in the mode of nonequilibrium depletion of MIS structures is designed. Methods of measurements were developed that provide a sensitivity of 0.03 pF and 0.02 pC along the capacitance and charge measurement channels with the acceleration time 1.5 ??s and 0.7 ??s, respectively. The results are obtained with a double amplitude of the test signal of capacitance measurement of ??15 mV and frequency 5 MHz. A mode of measuring the capacitance-voltage characteristics with a scanning duration up to 100 s is implemented.     

Determining the distance to a ferromagnetic object with unknown magnetic characteristics

The possibilities for determining the distance to a ferromagnetic object with unknown magnetic characteristics by the measurement of its magnetic field at two spatial points are considered. An unconventional measurement device, which allows us to determine the distance to an object in real time, as well as an algorithm and software for the processing of measurement results with the computer-generated visualization of the parameters of a magnetic field induced by an object, were developed. The error in determining the distance to a sought object does not exceed 20.0%.     

Determining the surface energy of tools in the aviation industry

The surface energy of a metal tool in the manufacture of aviation components is considered. It may be determined on the basis of measurement of the tool’s electron work function and subsequent calculation by a method that takes account of the electron structure and hardness of the material.     

Heat/mass transfer characteristics in the near-tip region on a turbine blade surface under combustor-level high inlet turbulence

Heat/mass transfer characteristics on the near-tip blade surface under combustor-level high inlet turbulence have been investigated within a high-turning turbine rotor passage by using the naphthalene sublimation technique. The inlet turbulence intensity and length scale are 14.7% and 80 mm, respectively. The tip gap-to-chord ratio is changed to beh/c = 0.74, 1.47, and 2.94 percents. Increasingh/c results not only in higher heat/mass transfer in the pressure-side tip region but also in more convective transport on the pressure surface even far away from the tip edge. Severe heat/mass transfer is always observed in the suction-side tip-leakage flow region which can be divided into two distinct high transport regions. There is a local maximum of heat/mass transfer along the trailing-edge centerline. This arises from the interaction of a tip-leakage vortex with a trailing-edge vortex shedding. Comparisons of the present data forh/c = 2.94 percents with the previous low turbulence one show that there is a large discrepancy of heat/mass transfer in the pressure-side near-tip area, which diminishes with departing from the tip edge. The suction-side heat/mass transfer in the tip-leakage flow region is less influenced by the high inlet turbulence than that at the mid-span. The leading-edge heat/mass transfer under the high inlet turbulence is always higher than that in the low turbulence case, while there is no big difference in the trailing-edge heat/mass transfer between the two cases.     

数控车床分体式床身结合面参数优化识别及其动特性分析

在机床动态试验的基础上 ,应用有限元理论建立了机床床身底座结构的动力学模型 ,并应用有限元分析软件AN SYS5 7的参量化设计语言APDL和该软件提供的优化模块 (DesignOptimizer) ,对床身与底座的结合面线性弹簧 -阻尼单元的刚度值进行了参数优化识别。最后对床身 -底座结构的动态特性进行了计算和分析 ,提出结构改进的建议     

Self-detection characteristics of the Sagnac frequency shift in a mechanically rotated semiconductor ring laser

Self-detection of the frequency difference between the two counter propagating oscillation frequencies in a mechanically rotated semiconductor ring laser (SRL) was successfully demonstrated. An SRL used for experiments consisted of a pig-tailed laser diode amplifier module. Detection characteristics of an SRL as an optical gyroscope were investigated and discussed. Beat frequency, which was detected by the terminal voltage change of an SRL without branching the circulating optical power, was measured as a function of the rotation rate, changing the loop radius for investigating the loop radius dependence on the detection sensitivity. The measured detection sensitivity characteristics coincided well with the theoretical prediction based on the Sagnac effect, and it was found that SRLs could be operated as optical gyroscopes. Furthermore, we verified that lock-in phenomenon was one of the most dominant noise sources in the S-RLG.     

Thickness characteristics and improved surface adhesion of a polypyrrole actuator by analysis of polymerization process

Characterizing electrochemical polymerization of polypyrrole film on a substrate depends on many parameters. Among them, potential difference and cumulative charges play important role. The level of potential difference affects the quality of the polypyrrole. On the contrary, cumulative charge affects the thickness of the polypyrrole. The substrate surface is adjusted physically and chemically by treating with sandblasting and the addition of thiol for surface adhesion improvement. Experimental results show that the sandblasted and thiol treated substrate provides better adhesion than non-sandblasted and non-thiol treated substrate.     

Plotting and analysis of hodographs for studying the electrophysical parameters of objects using attachable eddy-current transducers

The results of experimental studies during the eddy-current testing of conducting (including ferromagnetic) objects are considered. A data correcting procedure was suggested; it allows one to decrease the requirements for the phase and frequency stability characteristics of the measuring circuit and to relate experimental results to a theoretic model. Initial and corrected hodographs for a number of materials with different electrophysical properties are reported. The magnetic permeability magnitudes of steel 30X13 were calculated for two electromagnetic-field exciting frequencies (15 kHz and 1 MHz).     

Quantitative electron holographic tomography for the 3D characterisation of semiconductor device structures

Electron tomography and electron holography experiments have been combined to investigate the 3D electrostatic potential distribution in semiconductor devices. The experimental procedure for the acquisition and data reconstruction of holographic tilt series of silicon p-n junction specimens is described. A quantitative analysis of the experimental results from specimens of two different thicknesses is presented, revealing the 3D electrostatic potential variations arising from the presence of surfaces and damage generated by focused ion beam (FIB) sample preparation. Close to bulk-like properties are measured in the centre of the tomographic reconstruction of the specimen, revealing higher electrically active dopant concentrations compared to the measurements obtained at the specimen surfaces. A comparison of the experimental results from the different thickness specimens has revealed a 'critical' thickness for this specimen preparation method of 350nm that is required for this device structure to retain 'bulk'-like properties in the centre of the membrane.     

Radiation characteristics of getter materials in the region of a phase transformation

The results of studies of the radiation characteristics of samples of titanium and alloys thereof in the region of their polymorphous transformation and the temperature dependence of the emissivity in the β phase are presented. The calorimetric method of electron heating in high vacuum was used. It is shown that changes in the integral hemispherical emissivity ɛ _th for titanium iodide and industrial-grade titanium related to the transformation of a hexagonal close-packed lattice into a body-centered cubic lattice have different characters. Original Russian Text ? B.A. Shur, V.E. Peletskii, 2009, published in Pribory i Tekhnika Eksperimenta, 2009, No. 1, pp. 162–167.     

Assessment of surface texture from analysis of the signal visibility of a laser Doppler anemometer

A prospective new optical non-contact method for the assessment of surface texture is presented. A dual-beam laser Doppler anemometer is employed and the parameter “fringe visibility” is used as an indication of surface asperity size and geometry. The method was tested on specimens resulting from three different manufacturing processes, i.e. grinding, milling and turning, which possessed a range of R_a values from 0.025 to 50 μm. Both static and dynamic measurement configurations were examined.The experimental data are complemented by a review of the theoretical considerations and a computer model which considers the quantitative effects of variation in the relative asperity size, i.e. fringe spacing, and collection optics.     

Prediction and analysis of surface roughness characteristics of a non-ferrous material using ANN in CNC turning

Surface roughness, an indicator of surface quality is one of the most-specified customer requirements in a machining process. For efficient use of machine tools, optimum cutting parameters (speed, feed, and depth of cut) are required. So it is necessary to find a suitable optimization method which can find optimum values of cutting parameters for minimizing surface roughness. The turning process parameter optimization is highly constrained and non-linear. In this work, machining process has been carried out on brass C26000 material in dry cutting condition in a CNC turning machine and surface roughness has been measured using surface roughness tester. To predict the surface roughness, an artificial neural network (ANN) model has been designed through feed-forward back-propagation network using Matlab (2009a) software for the data obtained. Comparison of the experimental data and ANN results show that there is no significant difference and ANN has been used confidently. The results obtained conclude that ANN is reliable and accurate for predicting the values. The actual R _a value has been obtained as 1.1999???m and the corresponding predicted surface roughness value is 1.1859???m, which implies greater accuracy.