Showing papers in "Informacije Midem-journal of Microelectronics Electronic Components and Materials in 2015"

Research Challenges in Optical Communications Towards 2020 and Beyond

Abstract: This paper presents an overview of future research activities in the field of optical telecommunications. The year 2020 is considered a milestone, when the capacity of optical communication links via a single optical fiber will reach the physical limitation called the ”fiber wall”. It is expected that advances in systems with a standard, single-mode, optical fiber, which enables increasingly higher transmission capacities due to accelerated scientific research, will reach the point where the capacity of the optical link via a single optical fiber will no longer grow. Due to this collision with the ”fiber wall”, research efforts to develop future solutions are all the more necessary. This article provides an overview of the fields in which the future development of optical communications will give the most focus. In the field of optical devices and components, the development goes in the direction of integrated optics and new optical fibers. In order to achieve the objectives, the new communication techniques comprise coherent communications, multidimensional modulation formats and multiplexing techniques, as well as the use of digital signal processing. Modern optical networks extend from the high-performance fiber optic connections in the backbone to broadband access in user’s home, in the future their architecture will enable an adaptability to wavelength, bandwidth and modulation format. The main aim of the development towards 2020 and beyond is to build optical communication systems that will enable the transfer of large amounts of data with the minimum power consumption using the simplest and cheapest equipment.

Design of an active inductor based LNA in Silterra 130 nm CMOS process technology

Abstract: In this paper, an active inductor based CMOS low noise amplifier (LNA) has been illustrated for 2.4 GHz ISM band RF receivers. The proposed LNA has three stages: the common gate amplifier, the active inductor and the output buffer. The LNA is designed in Silterra 130-nm CMOS process. It operates at 1.2V supply voltage and exhibit a high gain (S21) of 33dB and reverse isolation (S12) of -33.1dB. The power dissipation of the LNA is only 1.51mW with 8.51 dB noise figure and 35.5dB IIP3. In the proposed LNA, active inductor circuit replaces the usual passive spiral inductor to keep the size of the chip area at 0.0004mm2. Such an LNA will be a better choice for high performance, fully integrated, low cost and low power RF receivers.

Radiation Behavior and Test Specifics of A-D and D-A Converters

Abstract: ADC/DAC radiation failures are mainly due to radiation-induced degradation of precision parameters of the transfer characteristic such as gain, zero offset, full-scale voltage, integral and differential non-linearity, conversion error. ADC/DAC radiation failure specifics is that even a slight deviation of electrical parameter of internal elements (comparator threshold, internal reference voltage, switch leakage, operational amplifier gain, etc.) often leads to significant degradation of ADC/DAC accuracy. ADC/DAC radiation test procedure and facilities are developed and test results are introduced.

Comparative Assesment of Ground Plane and Strained based FDSOI MOSFET

Abstract: In the present work, we have investigated the performance of ground plane and strained silicon on FDSOI MOSFETs. The 2D ATLAS simulations are done and the simulation model is validated with previously published experimental results. The transfer characteristics, DIBL, Vt, Ion and Ioff of all the structures are analyzed for 25 nm and 32 nm gate length. The effect of body thickness on device performance is also evaluated. Strained device offer higher drive current, but increases the leakage current. We have applied the ground plane to reduce the leakage current. The DIBL is higher for the strained device. DIBL in GPS and GPB structures (strained and unstrained) is almost same, and is lower than conventional FDSOI structure. The FDSOI devices have the lowest threshold voltage as compared to the GP and GPB devices, with GPB offering the highest Vt. The drain current is observed to increases almost linearly with body thickness. The deployment of ground plane and strained silicon on FDSOI MOSFET shows promise to substitute conventional MOSFET for high speed and low power applications.

Control of Electrical Conductivity in 0.7BiFeO3- 0.3SrTiO3 Ferroelectric Ceramics Via Thermal Treatment in Nitrogen Atmosphere and Mn Doping

Abstract: In this work, the solid solution between polar BiFeO3 (BFO) and non-polar SrTiO3 (ST) with the composition 0.7BFO-0.3ST has been prepared by mechanochemical activation-assisted synthesis with particular emphasis on the characterization and control of the electrical conductivity of the resulting ceramics. According to X-ray diffraction analysis and scanning electron microscopy the incorporation of ST into BFO minimizes the formation of secondary phases, typically formed during the synthesis of unmodified BFO. The as-sintered ceramics exhibited a high electrical conductivity, which was suppressed by post-annealing in N-2 atmosphere. However, this approach showed two major drawbacks: i) re-oxidation of samples and thus increase in their conductivity when annealed in air to elevated temperatures (up to similar to 450 degrees C) and ii) increased conductivity by application of high electrical fields, resulting in a strong leakage-current contribution to the measured polarization-electric-field hysteresis loops. For these reasons, in order to reduce the conductivity, we propose here an alternative approach, i.e., doping with MnO2. Using the doping, the specific conductivity has been decreased and did not deteriorate when the samples were heated in air to elevated temperatures. Unlike in the case of N-2-annealed samples, in the doped samples, saturated ferroelectric loops with negligible leakage-current contributions have been measured, revealing a coercive field of E-c similar to 80 kV/cm and a remanent polarization of 2Pr similar to 100 mu C/cm(2).

Micromachining of All-Fiber Photonic Micro-Structures for Microfluidic Applications

Abstract: Maskless micromachining of all-fiber photonics’ structures, based on the selective etching of structure forming optical fibers (SFF) is presented. A maskless micromachining process can reform or reshape a section of an optical fiber into a complex 3D photonic microstructure. This proposed micromachining process is based on the introduction of phosphorus pentoxide (P2O5) into silica glass through standard fiber manufacturing technology. Micro-machining is presented as a highly effective tool for the realization of new solutions in the design of optical sensors and microfluidic devices.

Computing Worst-Case Performance and Yield of Analog Integrated Circuits by Means of Mesh Adaptive Direct Search

Abstract: Estimating the parametric yield of a circuit by means of a Monte Carlo analysis can be slow, particularly when the yield estimate is close to 100%, as a large number of samples are necessary to reach the desired level of confidence. Deterministic numerical algorithms have been successfully used in commercial tools for yield estimation. Many of them are gradient-based. The gradients are estimated numerically using finite differences, because most simulators do not compute sensitivities. In this paper, an approach is proposed based on a derivative-free optimization algorithm from the family of mesh adaptive direct search methods. The basic algorithm is extended with capabilities that speed up the convergence and enable the algorithm to cope with infeasible starting points. The new approach is compared to a commercial tool that uses gradient-based algorithms for worst-case analysis. The results show that the proposed approach is capable of producing accurate results within similar computational budgets.

Linear Incremental Displacement Measurement System with Microtransformers

Abstract: The paper discusses an inductive microsensor system for displacement measurement comprising microtransformers. The primary windings of the microtransformers are excited with an AC source with a frequency of several MHz. The microtransformers are fabricated in internal metal layers of an integrated circuit using a conventional 350 nm commercial CMOS process, along with corresponding circuits for the processing of the microtransformers’ output signals. The major advantage of such system is its costeffectiveness due to its straightforward fabrication and the absence of the need for an external field generator, such as permanent magnets at Hall Effect encoders or a light source at optical encoders. In a linear incremental encoder application, microtransformer output signals are modulated by a metal measurement scale positioned over the integrated microsystem, resulting in a combination of amplitude and phase modulation. The integrated circuit employs a fullydifferential measurement channel with three-stage amplification and a mixer implemented with a Gilbert cell: the signal is demodulated using synchronous demodulation. A prototype microsystem was designed, fabricated and evaluated, demonstrating a sensitivity of 0.99 V/mm with a copper target at an approximate microsystem-target distance of 200-250 μm.

Spintronics as a Non-Volatile Complement to Modern Microelectronics

Abstract: Continuous miniaturization of semiconductor devices has been the main driver behind the outstanding increase of speed and performance of integrated circuits. In addition to a harmful active power penalty, small device dimensions result in rapidly rising leakages and fast growing stand-by power. The critical high power consumption becomes incompatible with the global demands to sustain and accelerate the vital industrial growth, and an introduction of new solutions for energy efficient computations becomes

Solution-derived Ba0.5Sr0.5TiO3 Thin-film Capacitors in Metal-insulator-metal Configuration

Abstract: The Ba0.5Sr0.5TiO3 (BST 50/50) thin films with the thicknesses ~250 nm were deposited on polycrystalline alumina substrates by Chemical Solution Deposition. The films were prepared by the multi-step annealing process at 750 °C, 800 °C and 900 °C and the effect of the annealing temperature on the phase composition, microstructure and dielectric properties of the films was studied. All BST 50/50 films crystallize in a pure perovskite phase after heating in a rapid thermal annealing furnace. The microstructure of the film annealed at 750 °C is granular with ~30 nm sized grains. As the annealing temperature increases to 800 °C the granular microstructure remains and the average lateral grain size increases to ~70 nm, while the film annealed at 900 °C consists of predominantly columnar grains with the average lateral size ~100 nm. The kHz-range dielectric permittivity increases from 350 for the film annealed at 750 °C to 480 for the film annealed at 900 °C.

Development of Testing Method for Smart Substations with Prosumers

Abstract: The paper presents a concept of design and realization of a new testing method for distribution substations which form a microgrid with prosumers. The distribution substation acts as a service provider for distributed resource units in a microgrid and can be used for bidirectional energy exchange between prosumers, such as electric vehicles, battery pack energy storage devices and utility networks. Use of distribution substations equipped with energy storing and bidirectional energy exchange capability enable peak load shaving and demand response, which will reduce the need for new investments into building new power sources or electric power grids to meet peak demand. While the state of the art in the field analyses mainly different theoretical microgrid topologies and integration of unidirectional distributed energy resources, focus in this paper is on practical issues regarding bidirectional energy exchange, which can provide solutions to microgrid manufacturing enterprises. Protection and control functions of the low voltage part of the distribution substation must be tested prior to exploitation. The new testing method for substations includes both computer simulations and practical verifications for automated energy exchange. Simulation results can be used to define and optimize parameters for protection and control functions before constructing a real microgrid. Functions of an experimental microgrid application were simulated with MATLAB, which showed that several prosumers can be served simultaneously and effectively utilized for peak shaving of utility network loads. The results of the simulations were used to develop sample control algorithms and program modules for the substation controller of the experimental microgrid prototype.