Particle-size analysis by laser diffraction with a complementary metal-oxide semiconductor pixel array

Existing laser-diffraction instruments that use photodiode detectors have a limited resolution for particle sizing. We attempt the implementation of a complementary metal-oxide semiconductor pixel sensor for particle-size measurement by laser diffraction. The sensor has unique features: high resolution, no blooming, and a wide dynamic range (i.e., direct measurement of the scattering pattern). The calibration of the sensor is based on each pixel. The signal-processing and the inversion schemes for obtaining the particle-size distribution are described. The results indicate an improved size resolution and an increased flexibility of application.     

0.18-microm complementary metal-oxide semiconductor push-pull vertical-cavity surface-emitting laser driver operating at 2.5 Gb/s with symmetric rising and falling edges

A vertical-cavity surface-emitting laser (VCSEL) driver design that utilizes a novel push-pull circuit topology is described. The VCSEL driver design can provide both a current pushing and a current pulling mechanism and therefore is capable of producing symmetric rise and fall times. The design was implemented in a 0.18-microm foundry n-well complementary metal-oxide semiconductor technology and operates at data rates up to 2.5 Gb/s with a power consumption of 45 mW at an average optical output power of 1 mW.     

Demonstration of synaptic and resistive switching characteristics in W/TiO2/HfO2/TaN memristor crossbar array for bioinspired neuromorphic computing

In this study,resistive random-access memory (RRAM)-based crossbar arrays with a memristor W/TiO2/HfO2/TaN structure were fabricated through atomic layer deposi...     

SiGe channels for VT control of high-k metal gate transistors for 32 nm complementary metal oxide semiconductor technology and beyond

GLOBALFOUNDRIES 32 nm high-k metal gate technology, with SiGe channel for V_T control of P-field effect transistor, is taken into production. This epitaxial channel material is being introduced into high volume manufacturing in complementary metal oxide semiconductor technology. The morphology of the SiGe channel (cSiGe) for narrow width transistors is carefully controlled by process conditions such as epitaxial growth temperature, pre bake condition or in-situ Si recess prior epitaxial deposition. A micro loading effect observed in 28 nm technology was eliminated by an in-situ recess of the silicon before epitaxial deposition. Due to the significant cost of this process step, an epitaxial batch system has been evaluated to reduce the cost of ownership dramatically. Also the cSiGe process has been optimized to minimize the thickness variation of the SiGe channel due to the strong response of V_T to cSiGe thickness.     

Optimised design of multi-band cellular base station antenna array for GSM and UMTS deployment

A tri-band dual polarised printed patch array is designed for GSM and UMTS cellular deployment using an efficient moment method code driven by a marginal distribution optimisation algorithm. Novel techniques are introduced to expedite analysis while maintaining adequate accuracy, and two methods are used to aggregate elements into an array for pattern synthesis: unequal spacing and phasing. Optimisation criteria such as crosspolar isolation, return loss and radiation pattern characteristics are successfully achieved in simulation, and a measured prototype element supports the antenna concept.     

红外焦平面失效元处理方法及软硬件实现

失效元对红外焦平面阵列器件成像质量的影响较大。本文在给出失效元定义的基础上,对失效元的产生机理进行了分析,并给出了具体的失效元检测方法。基于DSP实现了红外图像的硬件处理系统并编写了失效元处理的软件程序,实现了失效元的自动检测和校正。实验结果表明,所设计的软硬件符合实时性、可靠性的要求,取得了较好的处理效果。     

Inverse heat transfer analysis for design and control of a micro-heater array

A non-linear inverse heat source identification problem is described and solved. The inverse problem analysis is used in the design of an embedded micro-heater array and to estimate the required control settings, which are the input currents to each heating element, to generate as close as possible to a prescribed temperature profile on the surface of a thin copper film. The purpose of the micro-heater array is to control the local copper microstructure through control of the local temperature field. A finite element model of the micro-heater system is used to define a discrete set of non-linear equations used as a basis for the inverse problem solution. Two methods are explored to solve the inverse problem, a direct minimization method with Tikhonov regularization and a passivity-based feedback control algorithm. A uniform and a linear temperature distribution could be attained in the central region above the micro-heater array, but the temperatures near the edges of the domain could not be controlled due to heat loss at the edges. Thus, to control the temperature field over the full width of the domain, the heater array must extend beyond the domain of interest. Both methods to solve the inverse problem are found to perform well. The regularization method allows for a smoother solution, while the feedback control method is simpler as the coefficient matrix for which the update remains unchanged for each iteration.     

Dislocation array elements for the analysis of crack and yielded zone growth

Stress fields were found for boundary elements that consist of linear arrays of dislocations, or arrays of dislocations that simulate a crack tip. A number of two-dimensional elastic boundary value problems were solved using these elements. Crack growth paths were predicted for pairs of interacting cracks and the energetics of multiple crack growth away from a free surface was analysed. In certain simple elastic-plastic problems, where the general shape of the plastic zone is known, the plastic zone size was predicted.     

Application of integrated sensing and processing decision trees for target detection and localization on digital mirror array imagery

We demonstrate the applicability of integrated sensing and processing decision trees (ISPDTs) methodology to a set of digital mirror array (DMA) hyperspectral imagery. In particular, we demonstrate that ISPDTs can be used to detect and localize targets by using just a few DMA Hadamard frames, so that an entire hyperspectral data cube need not be collected to successfully perform the given task. This suggests that such an integrated sensing-processing suite may be appropriate for extremely time-sensitive pattern-recognition applications.     

Performance analysis of assembly/disassembly systems with unreliable machines and random processing times

This paper presents an efficient method to evaluate performance of tree-structured assembly/disassembly (AD) systems with finite buffer capacity. The times to failure, the times to repair, and the processing times are assumed to be exponentially distributed. The method is based on an extension of a decomposition method originally applied to performance evaluation of transfer lines. The method decomposes a K-machine tree-structured AD system to a system of K-1 two-machine lines and then finds the processing rates, failure rates and repair rates of the decomposed system that make performance of the two systems close to each other. To determine those rates of the decomposed system, we derive 6(K-1) equations based on interruption of flow, resumption of flow, and flow rate-idle time relations, and suggest two methods, which use the equations in different ways. Results from computational experiments show that the suggested decomposition methods give good estimates in a short time.     

Performance analysis of assembly/disassembly systems with unreliable machines and random processing times

This paper presents an efficient method to evaluate performance of tree-structured assembly/disassembly (AD) systems with finite buffer capacity. The times to failure, the times to repair, and the processing times are assumed to be exponentially distributed. The method is based on an extension of a decomposition method originally applied to performance evaluation of transfer lines. The method decomposes a K-machine tree-structured AD system to a system of K - 1 two-machine lines and then finds the processing rates, failure rates and repair rates of the decomposed system that make performance of the two systems close to each other. To determine those rates of the decomposed system, we derive 6(K - 1) equations based on interruption of flow, resumption of flow, and flow rate-idle time relations, and suggest two methods, which use the equations in different ways. Results from computational experiments show that the suggested decomposition methods give good estimates in a short time.     

Integration of a photodiode array and centroid processing on a single CMOS chip for a real-time shack-Hartmann wavefront sensor

A real-time VLSI optical centroid processor has been developed as part of a larger Shack-Hartmann wavefront sensor system for applications in adaptive optics. The implementation of the optical centroid detection system was demonstrated successfully using a hardware emulation system. Subsequently, the design has been implemented as a CMOS single-chip solution. This has advantages in terms of speed, power consumption, system size, and cost. The design of the different components of the system will be discussed along with test results of the fabricated device.     

Comparative analysis of triple band S-C-L erbium-doped fibre and semiconductor optical amplifier for CWDM applications

The authors present a comparative analysis between a triple-band S-C-L erbium-doped fibre amplifier and a commercial semiconductor optical amplifier in a CWDM application scenario. Both technologies were characterised for gain and noise figures from 1480 to 1610 nm (S, C and L bands) and their systemic performances were evaluated in terms of bit error rate measurements for a wide range of optical power levels.     

Factorial design,processing, characterization and microstructure analysis of PIP-based C/SiC composites

Polymer impregnation and pyrolysis (PIP) process-based C/SiC composites are fabricated using the in-house synthesized methyl-polycarbosilane (PCS). Two-level factorial design matrix is employed to carry out experiments to study the effect of four factors on flexural strength of the composite. Total sixteen sets of composite samples are fabricated. Response table, normal probability plot, ANOVA and regression analysis are carried out to determine the statistical significant factors. Composite density (\(\rho \)), fibre volume fraction (\(V_{\mathrm{f}}\)) and pyrolysis temperature (T) are found to be statistically significant, while softening point (SP) of the PCS and interaction of these four factors are found insignificant. Higher levels of the density and \(V_{\mathrm{f} }\) have shown positive effect, while the pyrolysis temperature has negative effect on the flexural strength of the composites. Flexural strength was found to be in the range of 374–592 MPa depending on the process parameters. The mechanical behaviour of the composites at different process conditions was explained with the help of their microstructures.     

Performance analysis of decision-feedback equalisation for cellular mobile radio with cochannel interference and fading

The error probability of minimum-mean-square-error decision-feedback equalisation (MMSE-DFE) is evaluated for digital cellular mobile radio systems in the presence of cochannel interference (CCI) and is compared with linear equalisation (LE). The main contribution of the paper is that this analysis accounts for pulse waveform, modulation and fading of the signal of interest, as well as the CCI. Quadrature-amplitude modulation (QAM) signalling in frequency-selective and quasi-static channels is considered. The CCI is treated as a stationary process, when caused by random phase and symbol-timing offsets relative to the signal of interest. Analysis includes techniques combining antenna diversity. The performance improvement as a function of taps in both feedforward and feedback filters is quantified. Owing to residual intersymbol interference (ISI) and CCI, the evaluation of the error probability is extremely complicated and time consuming in simulation. To overcome this issue, an efficient method based upon Gauss quadrature rules (GQR) is presented to compute the error probability. The method is not limited due to interference statistics and it yields remarkable advantages compared with other methods. The convergence of finite-length results to their infinite-length counterparts is also provided. Unlike the case of white noise, the simulations reveal that with the same finite length the DFE is unable to outperform the linear equaliser in a CCI-dominated channel if the feedback filter is of insufficient length.     

Dual-function photoelectrode of TiO2 nanotube array/CdZnS/ZnS heterojunction for efficient photoelectrochemical cathodic protection and anti-biofouling

The low photoelectric conversion efficiency of photoelectrode is an important factor that limits the ap-plication in photoelectrochemical cathodic protection(PECCP)field for marine anti-corrosion of metallic structures.In this work,a photoelectrode of TiO2/CdZnS/ZnS triple-phase heterojunction was fabricated by loading the narrow-band CdZnS associated with the broad-band ZnS via hydrothermal and continuous ion layer adsorption methods,respectively.The composite of CdZnS enhances the photoelectric conver-sion ability of TiO2,while the ZnS composite can prevent the CdZnS from photo-corrosion and suppress the spillover of the photogenerated electrons.The three-phase heterostructure effectively improves the PECCP performance on 316 L stainless steel(SS)under simulated solar irradiation,especially in 3.5 wt％NaCl solution without the sacrificial agent.In addition,the prepared TiO2/CdZnS/ZnS photoelectrode also performs anti-biofouling effect evidenced by the high removal efficiency of Pseudomonas aeruginosa(P.aeruginosa),which can be attributed to the oxidizability of photogenerated holes.The TiO2/CdZnS/ZnS triple-phase heterojunction with desirable performance is a promising semiconductor material for the applications of PECCP and anti-biofouling.     

Numerical analysis of transfer phenomena in semiconductor devices and structures 1. Universal program for two-dimensional modeling

A universal program for the two-dimensional numerical analysis of functionally integrated structures of integral circuits is described.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 51, No. 1, pp. 136–143, July, 1986.     

Principal component analysis: a versatile method for processing and investigation of XPS spectra

Given the relevance of principal component analysis (PCA) to the treatment of spectrometric data, we have evaluated potentialities and limitations of such useful statistical approach for the harvesting of information in large sets of X-ray photoelectron spectroscopy (XPS) spectra. Examples allowed highlighting the contribution of PCA to data treatment by comparing the results of this data analysis with those obtained by the usual XPS quantification methods. PCA was shown to improve the identification of chemical shifts of interest and to reveal correlations between peak components. First attempts to use the method led to poor results, which showed mainly the distance between series of samples analyzed at different moments. To weaken the effect of variations of minor interest, a data normalization strategy was developed and tested. A second issue was encountered with spectra suffering of an even slightly inaccurate binding energy scale correction. Indeed, minor shifts of energy channels lead to the PCA being performed on incorrect variables and consequently to misleading information. In order to improve the energy scale correction and to speed up this step of data pretreatment, a data processing method based on PCA was used. Finally, the overlap of different sources of variation was studied. Since the intensity of a given energy channel consists of electrons from several origins, having suffered inelastic collisions (background) or not (peaks), the PCA approach cannot compare them separately, which may lead to confusion or loss of information. By extracting the peaks from the background and considering them as new variables, the effect of the elemental composition could be taken into account in the case of spectra with very different backgrounds. In conclusion, PCA is a very useful diagnostic tool for the interpretation of XPS spectra, but it requires a careful and appropriate data pretreatment.     

Application of data envelopment analysis for cell performance evaluation and process improvement in cellular manufacturing

This paper proposes a methodology for cell performance evaluation and improvement which considers multiple cell inputs and outputs. A specific technique in data envelopment analysis called 'window analysis', which captures the cell efficiency changes over time, is modified and utilized in the methodology. The evaluation is performed by considering the local part families (manufactured in single cells) and the infrequent parts (manufactured in multiple cells) processed by a cell. A major contribution of this research is in proposing a new 'modified window analysis' technique for cell performance evaluation, and in demonstrating its effectiveness over the 'traditional window analysis'. Another contribution is in using the cross efficiency matrix to identify periods of best cell operating practices which aid management in cell process improvement.     

Proton-induced X-ray cross sections for selected elements Fe to As and applications of X-ray analysis to semiconductor systems

Ionization cross sections and K shell X-ray production cross sections for the elements Fe, Co, Cu, Zn, Ga, Ge and As have been measured for incident proton energies from 500 to 2000 keV. A 2 MV Van de Graaff was used to provide the protons and the X-ray energy spectra were measured with a high resolution Si(Li) detector. All measurements were made on thin targets (?x?10–30 μg/cm²) as determined by elastic proton scattering. Comparisons with the plane wave Born approximation and the binary encounter approximation theoretical models are made.Applications to Zn-implanted GaAsP have shown that, during an 850°C anneal process, a fraction of the implanted Zn is lost by out-diffusion through a deposited SiO₂ overcoat. Sensitivities for Zn in GaAsP are discussed. Profiling of As implanted in silicon by detecting the As Kα X-rays has shown a lower sensitivity limit of 2×10¹¹ As/cm² under the beam with the limiting factor attributed to the proton-induced bremsstrahlung from the silicon substrate. Measurements of Ni-chrome films have been made to determine alloy composition for different deposition conditions and sputtering threshold effects are observed for NiCr systems.