Search results for: semiconductor test.

Authors: Suchi Barua, Narottam Das, Sven Nordholm, Mohammad Razaghi

Abstract:

This paper presents nonlinear pulse propagation characteristics for different input optical pulse shapes with various input pulse energy levels in semiconductor optical amplifiers. For simulation of nonlinear pulse propagation, finite-difference beam propagation method is used to solve the nonlinear Schrödinger equation. In this equation, gain spectrum dynamics, gain saturation are taken into account which depends on carrier depletion, carrier heating, spectral-hole burning, group velocity dispersion, self-phase modulation and two photon absorption. From this analysis, we obtained the output waveforms and spectra for different input pulse shapes as well as for different input energies. It shows clearly that the peak position of the output waveforms are shifted toward the leading edge which due to the gain saturation of the SOA for higher input pulse energies. We also analyzed and compared the normalized difference of full-width at half maximum for different input pulse shapes in the SOA.

Keywords: Finite-difference beam propagation method, pulse shape, pulse propagation, semiconductor optical amplifier.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2370

Authors: Dil Nawaz Khan, M. H. Sayyad, Muhammad Yaseen, Munawar Ali Munawar, Mukhtar Ali

Abstract:

Effect of temperature and light was investigated on a thin film of organic semiconductor formyl-TIPPCu(II) deposited on a glass substrate with preliminary evaporated gold electrodes. The electrical capacitance and resistance of the fabricated device were evaluated under the effect of temperature and light. The relative capacitance of the fabricated sensor increased by 4.3 times by rising temperature from 27 to 1870C, while under illumination up to 25000 lx, the capacitance of the Au/formyl-TIPPCu(II)/Au photo capacitive sensor increased continuously by 13.2 times as compared to dark conditions.

Keywords: formyl-TIPPCu(II), Organic semiconductor, Photocapacitance, Polarizability.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1732

Authors: Youngji Yoo, Cheong-Sool Park, Jun Seok Kim, Young-Hak Lee, Sung-Shick Kim, Jun-Geol Baek

Abstract:

In the semiconductor manufacturing process, large amounts of data are collected from various sensors of multiple facilities. The collected data from sensors have several different characteristics due to variables such as types of products, former processes and recipes. In general, Statistical Quality Control (SQC) methods assume the normality of the data to detect out-of-control states of processes. Although the collected data have different characteristics, using the data as inputs of SQC will increase variations of data, require wide control limits, and decrease performance to detect outof- control. Therefore, it is necessary to separate similar data groups from mixed data for more accurate process control. In the paper, we propose a regression tree using split algorithm based on Pearson distribution to handle non-normal distribution in parametric method. The regression tree finds similar properties of data from different variables. The experiments using real semiconductor manufacturing process data show improved performance in fault detecting ability.

Keywords: Semiconductor, non-normal mixed process data, clustering, Statistical Quality Control (SQC), regression tree, Pearson distribution system.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1780

Authors: Q. Zafar, R. Akram, Kh.S. Karimov, T.A. Khan, M. Farooq, M.M. Tahir

Abstract:

In this study we present the effect of elevated temperatures from 300K to 400K on the electrical properties of copper Phthalocyanine (CuPc) based organic field effect transistors (OFET). Thin films of organic semiconductor CuPc (40nm) and semitransparent Al (20nm) were deposited in sequence, by vacuum evaporation on a glass substrate with previously deposited Ag source and drain electrodes with a gap of 40 μm. Under resistive mode of operation, where gate was suspended it was observed that drain current of this organic field effect transistor (OFET) show an increase with temperature. While in grounded gate condition metal (aluminum) – semiconductor (Copper Phthalocyanine) Schottky junction dominated the output characteristics and device showed switching effect from low to high conduction states like Zener diode at higher bias voltages. This threshold voltage for switching effect has been found to be inversely proportional to temperature and shows an abrupt decrease after knee temperature of 360K. Change in dynamic resistance (Rd = dV/dI) with respect to temperature was observed to be -1%/K.

Keywords: Copper Phthalocyanine, Metal-Semiconductor Schottky Junction, Organic Field Effect Transistor, Switching effect, Temperature Sensor

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2579

Authors: P. Acosta-Santamaría, A. Ibatá-Soto, A. López-Vásquez

Abstract:

Organic compounds in wastewaters coming from textile and pharmaceutical industry generated multiple harmful effects on the environment and the human health. One of them is the methyl orange (MeO), an azoic dye considered to be a recalcitrant compound. The heterogeneous photocatalysis emerges as an alternative for treating this type of hazardous compounds, through the generation of OH radicals using radiation and a semiconductor oxide. According to the author’s knowledge, catalysts such as TiO₂ doped with metals show high efficiency in degrading MeO; however, this presents economic limitations on industrial scale. Black sand can be considered as a naturally doped catalyst because in its structure is common to find compounds such as titanium, iron and aluminum oxides, also elements such as zircon, cadmium, manganese, etc. This study reports the photocatalytic activity of the mineral black sand used as semiconductor in the discoloration of MeO by oxidation and reduction photocatalytic techniques. For this, magnetic composites from the mineral were prepared (RM, M1, M2 and NM) and their activity were tested through MeO discoloration while TiO₂ was used as reference. For the fractions, chemical, morphological and structural characterizations were performed using Scanning Electron Microscopy with Energy Dispersive X-Ray (SEM-EDX), X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF) analysis. M2 fraction showed higher MeO discoloration (93%) in oxidation conditions at pH 2 and it could be due to the presence of ferric oxides. However, the best result to reduction process was using M1 fraction (20%) at pH 2, which contains a higher titanium percentage. In the first process, hydrogen peroxide (H₂O₂) was used as electron donor agent. According to the results, black sand mineral can be used as natural semiconductor in photocatalytic process. It could be considered as a photocatalyst precursor in such processes, due to its low cost and easy access.

Keywords: Black sand mineral, methyl orange, oxidation, photocatalysis, reduction.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1272

Authors: S.Aksoy, Y.Caglar

Abstract:

n-CdO/p-Si heterojunction diode was fabricated using sol-gel spin coating technique which is a low cost and easily scalable method for preparing of semiconductor films. The structural and morphological properties of CdO film were investigated. The X-ray diffraction (XRD) spectra indicated that the film was of polycrystalline nature. The scanning electron microscopy (SEM) images indicate that the surface morphology CdO film consists of the clusters formed with the coming together of the nanoparticles. The electrical characterization of Au/n-CdO/p–Si/Al heterojunction diode was investigated by current-voltage. The ideality factor of the diode was found to be 3.02 for room temperature. The reverse current of the diode strongly increased with illumination intensity of 100 mWcm-2 and the diode gave a maximum open circuit voltage Voc of 0.04 V and short-circuits current Isc of 9.92×10-9 A.

Keywords: CdO, heterojunction semiconductor devices, ideality factor, current-voltage characteristics

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2374

Authors: N. Dahbi, M. Daoudi, A.Belghachi

Abstract:

The present work deals with the calculation of transport properties of Hg0.8Cd0.2Te (MCT) semiconductor in degenerate case. Due to their energy-band structure, this material becomes degenerate at moderate doping densities, which are around 1015 cm-3, so that the usual Maxwell-Boltzmann approximation is inaccurate in the determination of transport parameters. This problem is faced by using Fermi-Dirac (F-D) statistics, and the non-parabolic behavior of the bands may be approximated by the Kane model. The Monte Carlo (MC) simulation is used here to determinate transport parameters: drift velocity, mean energy and drift mobility versus electric field and the doped densities. The obtained results are in good agreement with those extracted from literature.

Keywords: degeneracy case, Hg0.8Cd0.2Te semiconductor, Monte Carlo simulation, transport parameters.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1827

Authors: Hee-Guk Chae, Bo-Bae Song, Kyoung-Il Do, Jeong-Yun Seo, Yong-Seo Koo

Abstract:

In this study, an improved Electrostatic Discharge (ESD) protection circuit with low trigger voltage and high holding voltage is proposed. ESD has become a serious problem in the semiconductor process because the semiconductor density has become very high these days. Therefore, much research has been done to prevent ESD. The proposed circuit is a stacked structure of the new unit structure combined by the Zener Triggering (SCR ZTSCR) and the High Holding Voltage SCR (HHVSCR). The simulation results show that the proposed circuit has low trigger voltage and high holding voltage. And the stack technology is applied to adjust the various operating voltage. As the results, the holding voltage is 7.7 V for 2-stack and 10.7 V for 3-stack.

Keywords: ESD, SCR, latch-up, power clamp, holding voltage.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 989

Authors: M. K. Moazzam, A. Salmanpour, M. Nirouei

Abstract:

In this paper we have numerically analyzed terahertzrange wavelength conversion using nondegenerate four wave mixing (NDFWM) in a SOA integrated DFB laser (experiments reported both in MIT electronics and Fujitsu research laboratories). For analyzing semiconductor optical amplifier (SOA), we use finitedifference beam propagation method (FDBPM) based on modified nonlinear SchrÖdinger equation and for distributed feedback (DFB) laser we use coupled wave approach. We investigated wavelength conversion up to 4THz probe-pump detuning with conversion efficiency -5dB in 1THz probe-pump detuning for a SOA integrated quantum-well

Keywords: distributed feedback laser, nondegenerate fourwave mixing, semiconductor optical amplifier, wavelengthconversion

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1506

Authors: Davit Mirzoyan, Ararat Khachatryan

Abstract:

A process corner monitoring circuit (PCMC) is presented in this work. The circuit generates a signal, the logical value of which depends on the process corner only. The signal can be used in both digital and analog circuits for testing and compensation of process variations (PV). The presented circuit uses only metal-oxide-semiconductor (MOS) transistors, which allow increasing its detection accuracy, decrease power consumption and area. Due to its simplicity the presented circuit can be easily modified to monitor parametrical variations of only n-type and p-type MOS (NMOS and PMOS, respectively) transistors, resistors, as well as their combinations. Post-layout simulation results prove correct functionality of the proposed circuit, i.e. ability to monitor the process corner (equivalently die-to-die variations) even in the presence of within-die variations.

Keywords: Detection, monitoring, process corner, process variation.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1325

Authors: H. Kaatuzian, M. Sedghi, S. Khatami

Abstract:

In this paper, by exploiting a single semiconductor optical amplifier-Mach Zehnder Interferometer (SOA-MZI), an integratable all-optical flip-flop (AOFF) is proposed. It is composed of a SOA-MZI with a bidirectional coupler at the output. Output signals of both bar and crossbar of the SOA-MZI is fed back to SOAs located in the arms of the Mach-Zehnder Interferometer (MZI). The injected photon-rates to the SOAs are modulated by feedback signals in order to form optical flip-flop. According to numerical analysis, Gaussian optical pulses with the energy of 15.2 fJ and 20 ps duration with the full width at half-maximum criterion, can switch the states of the SR-AOFF. Also simulation results show that the SR-AOFF has the contrast ratio of 8.5 dB between two states with the transition time of nearly 20 ps.

Keywords: All Optical, Flip-Flop, Mach-Zehnder Interferometer (MZI), Semiconductor Optical Amplifier (SOA).

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2025

Authors: Bella Llego

Abstract:

This study aims to investigate the motivating and de-motivating factors that affect the learning ability of students attending the English Learning Center in Thailand. The subjects of this research were 20 students from the Hana Semiconductor Co., Limited. The data were collected by using questionnaire and analyzed using the SPSS program for the percentage, mean and standard deviation. The research results show that the main motivating factor in learning English at Hana Semiconductor Co., Ltd. is that it would help the employees to communicate with foreign customers and managers. Other reasons include the need to read and write e-mails, and reports in English, as well as to increase overall general knowledge. The main de-motivating factor is that there is a lot of vocabulary to remember when learning English. Another de-motivating factor is that when homework is given, the students have no time to complete the tasks required of them at the end of the working day.

Keywords: Motivating, demotivating, English learning center, student communicate.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1221

Authors: Srikanta Bose, S.K. Mazumder

Abstract:

In the present simulation work, an attempt is made to study the switching dynamics of an optically controlled 4HSiC thyristor power semiconductor device with the use of GaAs optically triggered power transistor. The half-cell thyristor has the forward breakdown of 200 V and reverse breakdown of more than 1000 V. The optically controlled thyristor has a rise time of 0.14 μs and fall time of 0.065 μs. The turn-on and turn-off delays are 0.1 μs and 0.06 μs, respectively. In addition, this optically controlled thyristor is used as a control switch for the DC-DC Boost converter. The pn-diode used for the converter has the forward drop of 2.8 V and reverse breakdown of around 400 V.

Keywords: 4H-SiC, Boost converter, Optical triggering, Power semiconductor device, thyristor.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1963

Authors: Youn-Sung Kim, Jin-Ho Jo, Mi-Sung Kim, Jae-Kun Lee

Abstract:

Accelerated life cycle test is applied to various products or components in order to reduce the time of life cycle test in industry. It must be considered for many test conditions according to the product characteristics for the test and the selection of acceleration parameter is especially very important. We have carried out the general life cycle test and the accelerated life cycle test by applying the acceleration factor (AF) considering the characteristics of brushless DC (BLDC) motor for washing machine. The final purpose of this study is to verify the validity by analyzing the results of the general life cycle test and the accelerated life cycle test. It will make it possible to reduce the life test time through the reasonable accelerated life cycle test.

Keywords: Accelerated life cycle test, reliability test, motor for washing machine, brushless dc motor test.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1883

Authors: Xiaohuan Li, Wangmin Yi, Xinghui Wu

Abstract:

In order to verify the performance of lunar lander structure, landing-impact test is urgently needed. And the test equipment is necessary for the test. The functions and the key points of the equipment are presented to satisfy the requirements of the test, and the design scheme is proposed. The composition, the major function and the critical parts’ design of the equipment are introduced. By the load test of releasing device and single-beam hoist, and the compatibility test of landing-impact testing system, the rationality and reliability of the equipment is proved.

Keywords: Landing-impact test, lunar lander, releasing device, test equipment.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1827

Authors: Omar Qasaimeh

Abstract:

The effect of the number of quantum dot (QD) layers on the saturated gain of doped QD semiconductor optical amplifiers (SOAs) has been studied using multi-population coupled rate equations. The developed model takes into account the effect of carrier coupling between adjacent layers. It has been found that increasing the number of QD layers (K) increases the unsaturated optical gain for K<8 and approximately has no effect on the unsaturated gain for K ≥ 8. Our analysis shows that the optimum ptype concentration that maximizes the unsaturated optical gain of the ground state is NA Ôëê 0.75 ×1018cm-3 . On the other hand, it has been found that the saturated optical gain for both the ground state and the excited state are strong function of both the doping concentration and K where we find that it is required to dope the dots with n-type concentration for very large K at high photon energy.

Keywords: doping, multilayer, quantum dot optical amplifier, saturated gain.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1927

Authors: A. Faruk Bakan, İsmail Aksoy, Nihan Altintaş

Abstract:

In this paper, half bridge DC-DC converters with transformer isolation presented in the literature are analyzed for highcurrent and low-voltage applications under the same operation conditions, and compared in terms of losses and efficiency. The conventional and improved half-bridge DC-DC converters are simulated, and current and voltage waveforms are obtained for input voltage Vdc=500V, output current IO=450A, output voltage VO=38V and switching frequency fS=20kHz. IGBTs are used as power semiconductor switches. The power losses of the semiconductor devices are calculated from current and voltage waveforms. From simulation results, it is seen that the capacitor switched half bridge converter has the best efficiency value, and can be preferred at high power and high frequency applications.

Keywords: Isolated half bridge DC-DC converter, high-current low-voltage applications, soft switching, high efficiency.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 5178

Authors: S. Zhuiykov, E. Kats

Abstract:

In recent times there has been a growing interest in the development of quasi-two-dimensional niobium pentoxide (Nb2O5) as a semiconductor for the potential electronic applications such as capacitors, filtration, dye-sensitised solar cells and gas sensing platforms. Therefore once the purpose is established, Nb2O5 can be prepared in a number of nano- and sub-micron-structural morphologies that include rods, wires, belts and tubes. In this study films of Nb2O5 were prepared on gold plated silicon substrate using spin-coating technique and subsequently by mechanical exfoliation. The reason this method was employed was to achieve layers of less than 15nm in thickness. The sintering temperature of the specimen was 800oC. The morphology and structural characteristics of the films were analyzed by Atomic Force Microscopy (AFM), Raman Spectroscopy, X-ray Photoelectron Spectroscopy (XPS).

Keywords: Mechanical exfoliation, niobium pentoxide, quazitwo- dimensional, semiconductor, sol-gel, spin-coating, two dimensional semiconductors.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2395

Authors: Chih Chin Yang, Chung Shan Sun

Abstract:

In this paper the relationships between professional competences and school curriculain IC design industry are explored. The semi-structured questionnaire survey and focus group interview is the research method. Study participants are graduates of microelectronics engineering professional departments who are currently employed in the IC industry. The IC industries are defined as the electronic component manufacturing industry and optical-electronic component manufacturing industry in the semiconductor industry and optical-electronic material devices, respectively. Study participants selected from IC design industry include IC engineering and electronic & semiconductor engineering. The human training with IC design professional competence in microelectronics engineering professional departments is explored in this research. IC professional competences of human resources in the IC design industry include general intelligence and professional intelligence.

Keywords: IC design, curricula, competence, task, duty.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1495

Authors: Masoud Saeedi, Shirin Rahimi Kazerooni, Vahid Parvaresh

Abstract:

Validity is an overriding consideration in language testing. If a test score is intended for a particular purpose, this must be supported through empirical evidence. This article addresses the validity of a multiple-choice achievement test (MCT). The test is administered at the end of each semester to decide about students' mastery of a course in general English. To provide empirical evidence pertaining to the validity of this test, two criterion measures were used. In so doing, a Cloze test and a C-test which are reported to gauge general English proficiency were utilized. The results of analyses show that there is a statistically significant correlation among participants' scores on the MCT, Cloze, and Ctest. Drawing on the findings of the study, it can be cautiously deduced that these tests measure the same underlying trait. However, allowing for the limitations of using criterion measures to validate tests, we cannot make any absolute claim as to the validity of this MCT test.

Keywords: C-test, cloze test, multiple-choice test, validity argument.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1924

Authors: Supachai Supmak, Yachai Limpiyakorn

Abstract:

Mutation testing can be applied for the quality assessment of test cases. Prioritization of mutation test generation has been a critical element of the industry practice that would contribute to the evaluation of test cases. The industry generally delivers the product under the condition of time to the market and thus, inevitably sacrifices software testing tasks, even though many test cases are required for software verification. This paper presents an approach of applying a social network centrality measure, PageRank, to prioritize mutation test generation. The source code with the highest values of PageRank, will be focused first when developing their test cases as these modules are vulnerable for defects or anomalies which may cause the consequent defects in many other associated modules. Moreover, the approach would help identify the reducible test cases in the test suite, still maintaining the same criteria as the original number of test cases.

Keywords: Software testing, mutation test, network centrality measure, test case prioritization.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 543

Authors: Takashi Shimizu, Tomoaki Hashimoto

Abstract:

Recently, crystal growth technologies have made progress by the requirement for the high quality of crystal materials. To control the crystal growth dynamics actively by external forces is useuful for reducing composition non-uniformity. In this study, a control method based on model predictive control using thermal inputs is proposed for crystal growth dynamics of semiconductor materials. The control system of crystal growth dynamics considered here is governed by the continuity, momentum, energy, and mass transport equations. To establish the control method for such thermal fluid systems, we adopt model predictive control known as a kind of optimal feedback control in which the control performance over a finite future is optimized with a performance index that has a moving initial time and terminal time. The objective of this study is to establish a model predictive control method for crystal growth dynamics of semiconductor materials.

Keywords: Model predictive control, optimal control, crystal growth, process control.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 829

Authors: Huaizhong Li, C.Peng Lam

Abstract:

State-based testing is frequently used in software testing. Test data generation is one of the key issues in software testing. A properly generated test suite may not only locate the errors in a software system, but also help in reducing the high cost associated with software testing. It is often desired that test data in the form of test sequences within a test suite can be automatically generated to achieve required test coverage. This paper proposes an Ant Colony Optimization approach to test data generation for the state-based software testing.

Keywords: Software testing, ant colony optimization, UML.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 3459

Authors: Rado Flajs, Miran Saje

Abstract:

We present a simple nonconforming approximation of the linear two–point boundary value problem which violates patch test requirements. Nevertheless the solutions, obtained from these type of approximations, converge to the exact solution.

Keywords: Generalized patch test, Irons' patch test, nonconforming finite element, convergence.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1549

Authors: Vincent King Soon Wong, Hong Seng Ng, Florinna Sim

Abstract:

Negative Bias Temperature Instability (NBTI) is one of the critical degradation mechanisms in semiconductor device reliability that causes shift in the threshold voltage (Vth). However, thorough understanding of this reliability failure mechanism is still unachievable due to a recovery characteristic known as NBTI recovery. This paper will demonstrate the severity of NBTI recovery as well as one of the effective methods used to mitigate, which is the minimization of measurement system delays. Comparison was done in between two measurement systems that have significant differences in measurement delays to show how NBTI recovery causes result deviations and how fast measurement systems can mitigate NBTI recovery. Another method to minimize NBTI recovery without the influence of measurement system known as Fast Wafer Level Reliability (FWLR) NBTI was also done to be used as reference.

Keywords: Fast vs slow BTI, Fast wafer level reliability, Negative bias temperature instability, NBTI measurement system, metal-oxide-semiconductor field-effect transistor, MOSFET, NBTI recovery, reliability.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1664

Authors: Yasuyuki Takahashi, Hayato Ishimura, Masao Miyagawa, Teruhito Mochizuki

Abstract:

Quantitative measurement of myocardium perfusion is possible with single photon emission computed tomography (SPECT) using a semiconductor detector. However, accumulation of ^99mTc-tetrofosmin in the liver may make it difficult to assess that accurately in the inferior myocardium. Our idea is to reduce the high accumulation in the liver by using dynamic SPECT imaging and a technique called time subtraction. We evaluated the performance of a new SPECT system with a cadmium-zinc-telluride solid-state semi- conductor detector (Discovery NM 530c; GE Healthcare). Our system acquired list-mode raw data over 10 minutes for a typical patient. From the data, ten SPECT images were reconstructed, one for every minute of acquired data. Reconstruction with the semiconductor detector was based on an implementation of a 3-D iterative Bayesian reconstruction algorithm. We studied 20 patients with coronary artery disease (mean age 75.4 ± 12.1 years; range 42-86; 16 males and 4 females). In each subject, 259 MBq of ^99mTc-tetrofosmin was injected intravenously. We performed both a phantom and a clinical study using dynamic SPECT. An approximation to a liver-only image is obtained by reconstructing an image from the early projections during which time the liver accumulation dominates (0.5~2.5 minutes SPECT image-5~10 minutes SPECT image). The extracted liver-only image is then subtracted from a later SPECT image that shows both the liver and the myocardial uptake (5~10 minutes SPECT image-liver-only image). The time subtraction of liver was possible in both a phantom and the clinical study. The visualization of the inferior myocardium was improved. In past reports, higher accumulation in the myocardium due to the overlap of the liver is un-diagnosable. Using our time subtraction method, the image quality of the ^99mTc-tetorofosmin myocardial SPECT image is considerably improved.

Keywords: 99mTc-tetrofosmin, dynamic SPECT, time subtraction, semiconductor detector.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1033

Authors: H. Paredes Gutiérrez, S. T. Pérez-Merchancano

Abstract:

Motivated by recent experimental and theoretical developments, we investigate the influence of embedded quantum dot (EQD) of different geometries (lens, ring and pyramidal) in a double barrier heterostructure (DBH). We work with a general theory of quantum transport that accounts the tight-binding model for the spin dependent resonant tunneling in a semiconductor nanostructure, and Rashba spin orbital to study the spin orbit coupling. In this context, we use the second quantization theory for Rashba effect and the standard Green functions method. We calculate the current density as a function of the voltage without and in the presence of quantum dots. In the second case, we considered the size and shape of the quantum dot, and in the two cases, we worked considering the spin polarization affected by external electric fields. We found that the EQD generates significant changes in current when we consider different morphologies of EQD, as those described above. The first thing shown is that the current decreases significantly, such as the geometry of EQD is changed, prevailing the geometrical confinement. Likewise, we see that the current density decreases when the voltage is increased, showing that the quantum system studied here is more efficient when the morphology of the quantum dot changes.

Keywords: Quantum semiconductors, nanostructures, quantum dots, spin polarization.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 956

Authors: Chang Soo Kang, In Ho Im, Sergey Churayev, Timour Paltashev

Abstract:

This paper describes the design of new method of propagation delay measurement in micro and nanostructures during characterization of ASIC standard library cell. Providing more accuracy timing information about library cell to the design team we can improve a quality of timing analysis inside of ASIC design flow process. Also, this information could be very useful for semiconductor foundry team to make correction in technology process. By comparison of the propagation delay in the CMOS element and result of analog SPICE simulation. It was implemented as digital IP core for semiconductor manufacturing process. Specialized method helps to observe the propagation time delay in one element of the standard-cell library with up-to picoseconds accuracy and less. Thus, the special useful solutions for VLSI schematic to parameters extraction, basic cell layout verification, design simulation and verification are announced.

Keywords: phase error accumulation methodology, gatepropagation delay, Processor Testing, MEMS Testing

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1499

Authors: Fuyang Peng, Bo Deng, Chao Qi

Abstract:

This paper presents the design and implementation of CASTE, a Cloud-based automatic software test environment. We first present the architecture of CASTE, then the main packages and classes of it are described in detail. CASTE is built upon a private Infrastructure as a Service platform. Through concentrated resource management of virtualized testing environment and automatic execution control of test scripts, we get a better solution to the testing resource utilization and test automation problem. Experiments on CASTE give very appealing results.

Keywords: Software testing, test environment, test script, cloud computing, IaaS, test automation.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2178

Authors: C. Kalamani, K. Paramasivam

Abstract:

Test data compression is an efficient method for reducing the test application cost. The problem of reducing test data has been addressed by researchers in three different aspects: Test Data Compression, Built-in-Self-Test (BIST) and Test set compaction. The latter two methods are capable of enhancing fault coverage with cost of hardware overhead. The drawback of the conventional methods is that they are capable of reducing the test storage and test power but when test data have redundant length of runs, no additional compression method is followed. This paper presents a modified Run Length Coding (RLC) technique with Multilevel Selective Huffman Coding (MLSHC) technique to reduce test data volume, test pattern delivery time and power dissipation in scan test applications where redundant length of runs is encountered then the preceding run symbol is replaced with tiny codeword. Experimental results show that the presented method not only improves the test data compression but also reduces the overall test data volume compared to recent schemes. Experiments for the six largest ISCAS-98 benchmarks show that our method outperforms most known techniques.

Keywords: Modified run length coding, multilevel selective Huffman coding, built-in-self-test modified selective Huffman coding, automatic test equipment.

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1274