Papers by Keyword: Microelectronics

Abstract: The performance of the SiO₂ MOSFET-based absorber as a solution to arching within transmission lines (used for RF signal transportation) has been realized and analyzed at 28 GHz using the reflected signal from the R_X branch of 5G massive MIMO base station. The reflected signal from the receiver (R_X) branch of base stations may lead to interference, thus creating a performance reducing condition (arching) within the transmission lines. For optimum performance in the 5G regime, the SiO₂ MOSFET has been used to solve the problem of arching within the transmission line under large field intensities of a standing wave resulting from the impedance. The SiO₂ MOSFET-based absorber has been observed for a reflectivity of -79.5 dB and a rectification efficiency greater than 17 %

Abstract: This paper presents system performance indices for a class-B power amplifier using Double-Gate (DG) Metal Oxide Semiconductor Field Effect Transistor (MOSFET). It also presents a comparative analysis of three power amplifiers using different switching devices, i.e. Bipolar Junction Transistor (BJT), MOSFET, and DG MOSFET. The MOSFET used in this research work is based on Silicon for n-MOSFET and SiO₂ has been used as oxide layer. These power amplifiers are also being designed and simulated to test the speed and time (taken for each of these power amplifiers) to get the output signal when an input signal is applied. A comparison of these three power amplifier circuits is taken in the tabular form to conclude which power amplifier circuit performs better regarding its switching speed and the time. Switching speed relates with the time taken to amplify the signal, which is the same as its time to amplify the signal to a specific gain. Settling time for these three types of power amplifiers have also been tested and presented for the performance of these power amplifiers.

Abstract: Efficient cleaning of contaminations in the semiconductor industry is a determining factor in ensuring the good quality of the electronics products. We present here the dynamic wetting characterization of a fluid on top of DTI structures using ultra-high frequency acoustic method. The dynamics of the fluid will be established using a PDMS micro-channel placed on top of the structures, in order to obtain conditions as close as possible to those used in the industrial process. Wetting state of the DTI structures is determined based on the measured acoustic reflection coefficient.

Abstract: Modern electronics is based on semiconductor nanostructures in practically all main parts: from microprocessor circuits and memory elements to high frequency and light-emitting devices, sensors and photovoltaic cells. Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) with ultimately low gate length in the order of tens of nanometers and less is nowadays one of the basic elements of microprocessors and modern electron memory chips. Principally new physical peculiarities of semiconductor nanostructures are related to quantum effects like tunneling of charge carriers, controlled changing of energy band structure, quantization of energy spectrum of a charge carrier and a pronounced spin-related phenomena. Superposition of quantum states and formation of entangled states of photons offers new opportunities for the realization of quantum bits, development of nanoscale systems for quantum cryptography and quantum computing. Advanced growth techniques such as molecular beam epitaxy and chemical vapour epitaxy, atomic layer deposition as well as optical, electron and probe nanolithography for nanostructure fabrication have been widely used. Nanostructure characterization is performed using nanometer resolution tools including high-resolution, reflection and scanning electron microscopy as well as scanning tunneling and atomic force microscopy. Quantum properties of semiconductor nanostructures have been evaluated from precise electrical and optical measurements. Modern concepts of various semiconductor devices in electronics and photonics including single-photon emitters, memory elements, photodetectors and highly sensitive biosensors are developed very intensively. The perspectives of nanostructured materials for the creation of a new generation of universal memory and neuromorphic computing elements are under lively discussion. This paper is devoted to a brief description of current achievements in the investigation and modeling of single-electron and single-photon phenomena in semiconductor nanostructures, as well as in the fabrication of a new generation of elements for micro-, nano, optoelectronics and quantum devices.

Abstract: The sol-gel synthesis of filled aluminosilicates (FAS) has been developed. Such FAS consist of dendrimer morphology macromolecules capable to accommodate as a filler up to 70 % wt of high-refractory nitrides and oxides of high-melting compounds. The study of the obtained ceramic coatings on the developed metal surfaces has showed their use prospects to develop an ion beam control electrode in the ion plasma machine, microelectronics, and LED technology.

Abstract: In this paper, we propose a novel methodology to automate the transistor-level sizing of OpAmps. Given the netlist and the specifications of the OpAmp, our methodology automatically produces a set of monomial design equations that can be solved using a geometric programming. The use of monomial models eliminates the overhead of generating elaborate posynomial design equations. This approach produces a design that has the accuracy of the BSIM models used for simulation and the advantage of a quick design time. The results of a two stage OpAmp designed in TSMC 0.25μ technology prove the efficacy of our approach.

Abstract: —In view of the inefficiency of coding, the complexity of signal extraction and the strict demands of machining in the existing multiple SAW tags system, an anti-collision technique based on Walsh Code was proposed. First, it encodes the 2PSK using the single antenna transmission structure, then it implements the orthogonal encoding of each tag in a multiple SAW tags system using Walsh coding, and finally the encoding information of each tag is acquired by reading the echo signals from the reader and doing cross-correlation operation with each code block in the orthogonal code-set. The proposed approach incorporates both the coding efficiency and the processing technology, simplifies the complexity of signal extraction, and achieves the goal of anti-collision of multiple SAW tags system. The theoretical analysis and simulation verify the feasibility of this technique.

Abstract: As a new promising integrating and packing technology, the low temperature co-fired ceramic (LTCC) technology shows great potential in the microelectronics field and attracts great attentions for the scholars at home and abroad. In this paper, the practical application of LTCC is introduced and the emphasis is focused on the ways to the main problems in the application. As to this point, some advices are also given for the future development.

Abstract: Nanocrystalline composite powders were prepared by mechanical alloying of pure Cu, Fe and Co as metallic major part and Al₂O₃ or Fe₂O₃ or SiO₂ as ceramic reinforcement in a high-energy ball mill. Alloys of the copper-iron-cobalt system are promising for the development of new materials and applications. Cu-Fe-Co is used in different applications depending on the properties required. These can be related for example to toughness when used as rock cutting tool, to magnetic and electric properties for microelectronics or to chemical behaviour when used as catalysts in bioalcohol production industry. The objective of the present study is to contribute to understanding how and to which amount the ceramic reinforcement affects the properties for which this Cu-Fe-Co system is used as well as to envisage other less frequently uses for the composite powders. Structural and magnetic transformations occurring in the material during milling were studied with the use of X-ray diffraction, scanning quantum induction device (SQUID) and magnetic force microscopy (MFM). In mechanical alloying the transformations depend upon milling time. The results showed that milling the elemental powders of Cu-Fe-Co in the mass proportion of 50:25:25 respectively for times up to 10h leads to the progressive dissolution of Fe and Co atoms into FCC Cu and the final product of the MA process was the nanocrystalline Cu containing Fe and Co with a mean crystallite size (from coherent crystal size determination by diffraction) of 20 nm aprox. When ceramic particles are milled together with the metals (at proportions of the oxides between 1-10%) this mechanism is retarded. On the other hand, the lowest mean crystallite size is reached without ceramic particles in the milling process. However the composite powder produced in all the cases stabilized similar lowest crystallite size between 45-50 nm. Mechanically alloyed metallic-ceramic composite powder showed lower saturation magnetization than the metallic system but enhanced coercive field (significantly for hematite reinforcement). All the studied systems are intermediate ferromagnetics (H_c≈104 A/m). Milling time significantly affects the structure, composition and properties for both metallic and composite systems.

Abstract: This work is related to reliability of strain measurement in flexible printed circuit boards (fPCBs) made with polyimide substrate. It was observed that the fPCBs are very sensitive to strain mounting stiffness. The indirect measurement method will be done employing High Speed Camera (HSP). The direct method will be formulated in two ways: 1) conventional strain gauge glued in an fPCBs; 2) printed strain gauge in a polyimide substrate. This paper will point out mistakes and show advantages when using different method to extract the deformation field of the selected area in a flexible thin film.