A surface potential based drain current model for asymmetric double gate MOSFETs

In this paper, we present a generic surface potential based current voltage (I-V) model for doped or undoped asymmetric double gate (DG) MOSFET. The model is derived from the 1-D Poisson’s equation with all the charge terms included and the channel potential is solved for the asymmetric operation of DG MOSFET based on the Newton-Raphson iterative method. A noncharge sheet based drain current model based on the Pao-Sah’s double integral method is formulated in terms of front and back gate surface potentials at the source and drain end. The model is able to clearly show the dependence of the front and back surface potential and the drain current on the terminal voltages, gate oxide thicknesses, channel doping concentrations and the Silicon body thickness and a good agreement is observed with the 2-D numerical simulation results.     

A 2‐D surface‐potential‐based threshold voltage model for short channel asymmetric heavily doped DG MOSFETs

In recent times, transistors with heavily doped body have generated much interest because of junctionless channel. In addition, proper threshold voltage regulation requires adjustment of the channel doping, as a result of which most of the compact models become invalid as they consider an intrinsic body. In this paper, a compact surface‐potential‐based threshold voltage model is developed for short channel asymmetric double‐gate metal–oxide–semiconductor field‐effect transistors with heavily/lightly doped channel. The 2‐D surface potential is computed and compared with Technology Computer Aided Design, and a relative error of 2–4 % was obtained. The threshold voltage is solved from 2‐D Poisson's equation using ‘virtual cathode’ method, and a good agreement is observed with the numerical simulations. Also, the model is compared with a reference model and a better result is obtained for heavily doped channel. Copyright © 2014 John Wiley & Sons, Ltd.     

Effect of sinusoidal cylindrical surface of PCM on melting performance

Journal of Mechanical Science and Technology - A numerical analysis was conducted to examine the effect of capsule shape on phase change material (PCM) melting speed. The surface parameters of the...     

Studies on electro‐conductive yarns prepared by in situ chemical and electrochemical polymerization of pyrrole

This work deals with preparation, characterization, and performance of electro‐conductive yarns prepared by in situ chemical and electrochemical polymerization of pyrrole. Box‐Behnken design in conjunction with response surface analysis has been used to study the electrochemical polymerization process. The effect of electrochemical process parameters on the electrical resistivity has been reported. Further, the electrical and electromechanical behaviour of the electro‐conductive yarns thus produced has also been reported. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Effect of copper (II) chelate on photodegradation of poly (1-butene)

Photo-oxidative degradation of isotactic poly(1-butene) in the presence and absence of copper (II) bis-(1,3-diphenyl triazine-N-oxide) chelate has been studied, by measuring the weight average molecular weight, measuring changes in the carbonyl groups and by measuring changes in the hydroperoxide contents in the temperature range of 267 to 313 K using monochromatic light of wavelength 253.7 nm. The mechanism leading to the stabilization observed, resulting from the addition of chelate, is discussed.     

Analytical modeling of flicker and thermal noise in n-channel DG FinFETs

A compact physics-based thermal and flicker noise model has been developed for n-channel Double Gate FinFETs with varying structural parameters. The effects of mobility degradation due to velocity saturation, carrier heating and channel length modulation have been incorporated for an accurate modeling of noise. The mobility fluctuations dependent on the inversion carrier density have been considered and a characteristic of the flicker noise different from that of Bulk MOSFETs was observed. This has been validated by the experimental results. Based on the proposed thermal and flicker noise model, a compact expression of the corner frequency has been derived and the effects of the structural parameters such as the length and the thickness of the channel have been analyzed. Finally, the model has been applied for p-channel devices and noise behavior in accordance with experimental data has been obtained.     

Analysis of geometric errors associated with five-axis machining centre in improving the quality of cam profile

A five-axis machine is presently one of the most versatile machine tools available and they are becoming increasingly common. To increase the accuracy capabilities of such machines, it is crucial to be able to study the geometric errors of the components and its effect on the quality of machined products. In five-axis machine tools, all linear axes are theoretically perpendicular (dot product, cos 90°=0) to each other and directed along or around the X, Y and Z of the cartesian coordinate system; but in working machines, the axes are nearly perpendicular (cos89.90°≠0) because of manufacturing error and assembly error or quasi-static error. The present paper discusses the development of a generalised error model for the effects of geometric errors of the components of the kinematic chain of a machine in the workspace and the results obtained by this model have been verified experimentally. The effect of geometric error has been studied further for cam profile generation using a five-axis machining centre and an improvement in the profile has been obtained.     

Performance and optimisation of dual material gate short channel BULK MOSFETs for analogue/mixed signal applications

The challenge of analogue operation of CMOS devices and its parameters is a very important study for future technologies. In this article, the performance of dual material gate bulk MOSFETs for analogue/mixed signal applications is explored. Moreover, the optimisation of the device is done based on the variation of length and work-function difference of the two gate metals. The effect of drain induced barrier lowering in this structure is studied in detail. Moreover the different analogue parameters such as transconductance (g _m), output resistance (R _o) tuning for high performance of the device are also investigated by extensive simulations.     

Effect of pyrophyllite on vitrification and on physical properties of triaxial porcelain

Quartz was progressively replaced by pyrophyllite in a conventional porcelain mix with a composition of 50% clay, 25% quartz and 25% feldspar. The addition resulted in early vitrification and decreased thermal expansion of the sintered specimen. Addition of up to 15% pyrophyllite decreased the fired shrinkage by 6% and improved the fired strength by around 29% compared to the standard body. The gradual increase in flexural strength with incorporation of pyrophyllite was primarily due to the elimination of stresses in the structure with a decreasing quartz content as well as to the increasing amount of secondary mullite distributed throughout the matrix forming an interlocking network. However, the firing temperature and the generation of the correct amount of properly sized mullite needles are vital in achieving the desired strength. Pyrophyllite was found to dissolve in the melt in preference to quartz. Beyond the optimum proportion of pyrophyllite, a large volume of glass formed as well as large elongated pores distributed in the matrix resulting in deterioration of mechanical properties.