RF/analog and linearity performance analysis of SiGe source ETLTFET with emphasis on temperature

This study comprises a simulated assessment of the influence of temperature on transfer characteristics of SiGe source-based Epitaxial layer tunnel field effect transistor (SiGe source ETLTFET). Using the transfer characteristics, the temperature dependence of the RF/analog parameters: transconductance (g_m), intrinsic capacitances, cut-off frequency (f_T), transconductance generation factor (TGF), transconductance frequency product (TFP), transit time (τ) and minimum noise figure (NF_min) are also presented. Finally, the linearity metrics including higher-order transconductance (g_m2 and g_m3), input intercept point (IIP₃), voltage intercept point (VIP₃), intermodulation distortion (IMD₃), and 1-dB compression point was evaluated for a wide range of temperature. The findings revealed a substantial impact of temperature on the RF/analog and linearity characteristics. As the temperature rises from 250 to 350 K, the RF/analog characteristics improved, but the linearity figure of merits deteriorates. Moreover, a degraded noise performance (NF_min increases) of the device at elevated temperature was also witnessed.

     

3D analytical modeling of surface potential,threshold voltage,and subthreshold swing in dual-material-gate (DMG) SOI FinFETs

Here, we develop a 3D analytical model for potential in a lightly doped dual-material-gate FinFET in the subthreshold region. The model is based on the perimeter-weighted sum of a dual-material double-gate (DMDG) asymmetric MOSFET and a DMDG symmetric MOSFET. The potential model is used to determine the minimum surface potential needed to obtain the threshold voltage \((V_{\mathrm{T}})\) and subthreshold swing (SS) by considering the source barrier changes in the leakiest channel path. The proposed model is capable of reducing the drain-induced barrier lowering (DIBL) as well as the hot carrier effects offered by this device. The impact of control gate ratio and work function difference between the two metal gates on \(V_{\mathrm{T}}\) and SS are also correctly established by the model. All model derivations are validated by comparing the results with technology computer-aided design (TCAD) simulation data.     

Reliable $$H_{\infty }$$ Stabilization of Fuzzy Systems with Random Delay Via Nonlinear Retarded Control

In this paper, the robust reliable \(H_\infty \) control problem has been investigated for a class of nonlinear discrete-time TS fuzzy systems with random delay. In particular, the proposed fuzzy system consists of local nonlinear models with set of fuzzy rules, but the conventional TS fuzzy systems has local linear models. Our attention is focused on the design of a feedback reliable nonlinear retarded control law to ensure the robust asymptotic stability for nonlinear discrete-time TS fuzzy system with admissible uncertainties as well as actuator failure cases and random delay. In particular, by using an input delay approach, the random delay with stochastic parameters in the system matrices is introduced in the system model. Based on the Lyapunov approach, firstly, a sufficient condition for asymptotic stability is proposed for TS fuzzy systems in the presence of actuator failures. Then, a robust reliable \(H_\infty \) control is designed for the uncertain TS fuzzy system by solving a strict linear matrix inequalities using the available numerical software. Finally, a numerical example based on real-time ball and beam system is provided to validate the effectiveness of the proposed design technique.     

Pilot-scale manufacturing of phase-pure and highly crystalline hydroxyapatite: Lessons learned and process protocols

The recognition of hydroxyapatite (HAp) as the major bone mineral triggered significant research in bone tissue engineering applications. Although laboratory-scale development involves the synthesis of HAp in different routes, scalability with uncompromised quality remains a major challenge. This article reports a large-scale wet precipitation-based synthesis of phase-pure HAp using indigenously customized stirred tank reactors. The different synthesis parameters, like pH, reaction time, stirring rate, precursor addition, were tailored, together with the post-synthesis mechano-chemical treatment (aging induced Ostwald ripening) and calcinations, as the technology is matured to manufacture HAp powders in large volume. At least three batches of HAp were produced in the pilot-scale reactor with reproducible values of phase purity, compositional fingerprint, particle size distribution, flowability, etc. The post-calcination bluish tint was strategically addressed by adopting a proprietary calcination protocol. This batch process can produce around 200 kg/month of phase-pure and highly crystalline (91–94%) HAp using stirred tank reactors of different working volumes. Extensive scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses reveal the particle size of as-synthesized HAp powders with hexagonal crystal structure in the range of 20.47 ± 4.95 nm , while individual crystallite size in range of 22.3 ± 3.2 nm (XRD based Debye-Scherrer analysis). TEM-based SADP analysis confirms the highly crystalline hexagonal structure of as-synthesized HAp. The spray-dried powders with spherical shape having narrow size distribution (35–40 μm) could also be manufactured in large batches. The spray-dried HAp powders could be coated on clinically used stainless steel femoral stem implants using atmospheric plasma spray coating technique.     

A threshold voltage model for short-channel MOSFETs taking into account the varying depth of channel depletion layers around the source and drain

In this paper, an analytical model for threshold voltage of short-channel MOSFETs is presented. For such devices, the depletion regions due to source/drain junctions occupy a large portion of the channel, and hence are very important for accurate modeling. The proposed threshold voltage model is based on a realistic physically-based model for the depletion layer depth along the channel that takes into account its variation due to the source and drain junctions. With this, the unrealistic assumption of a constant depletion layer depth has been removed, resulting in an accurate prediction of the threshold voltage. The proposed model can predict the drain induced barrier lowering (DIBL) effect and hence, the threshold voltage roll-off characteristics quite accurately. The model predictions are verified against the 2-D numerical device simulator, DESSIS of ISE TCAD.     

Water repellent finishing on eri silk fabric using nano silica

Abstract

Nano silica was extracted from rice husk and applied on eri silk fabric to impart water repellency. The efficiency of the water repellency was evaluated with water contact angle, water absorbency and spray test methods. In order to enhance the water repellent properties, a silicone-based polymer was also applied. The effect of nano silica coating on the physico-mechanical properties of the eri silk fabric was studied using standard methods. SEM, FTIR and EDX techniques were used for the confirmation of presence of nano silica on silk fabric. The results inferred the nano silica imparted hydropholic property to eri silk fabric, which was further enhanced to superhydrophobic by the incorporation of silica polymer. The nano silica coating slightly enhanced the whiteness and brightness of eri silk fabric. Other mechanical parameters like bending rigidity and crease recovery angle were found to be intact. The higher concentration of nano silica caused a slight reduction in fabric tensile strength.     

A Tunneling Current Model with a Realistic Barrier for Ultra-Thin High-k Dielectric ZrO2 Material Based MOS Devices

In this paper, a theoretical model to estimate the tunneling current density of ultra-thin MOS devices is presented. First an ideal barrier has been assumed for the modeling. Then development in the results is brought in by taking into account the barrier height lowering due to the image force effect (practical barrier). The SiO₂ material with selected high-k dielectric material ZrO₂ based MOS structure is used to verify the tunneling current density model against the 2-D device simulator, ATLAS of Silvaco TCAD for a wide variation of oxide thickness and biasing conditions having doping concentration of 5 × 10¹⁷ cm^− 3. Tunnel resistivity is also evaluated utilizing this tunneling current density model. Excellent agreement between the two are observed.

     

Decentralised coverage of a large structure using flocking of autonomous agents having a dynamic hierarchy model

Autonomous Robots - In this paper, we present a decentralised algorithm to form a coverage around a large structure using autonomous sensor agents. Forming a coverage around a structure is defined...     

A surface potential and quasi-Fermi potential based drain current model for pocket-implanted MOS transistors in subthreshold regime

A subthreshold drain current model for pocket-implanted MOS transistors, incorporating both the drift and diffusion currents, is presented in this paper. In this model, the concept of splitting of the quasi-Fermi energy levels under nonequilibrium condition is used. It is well known that the surface potential based drain current models strongly depend on the potential profile of the channel. For short-channel devices, the end effect at the source and drain ends on the surface potential, and consequently on the drain current, cannot be ignored. The end effect gives rise to a position dependent potential profile, in contrast to a flat 1D profile in a long-channel device; which implies that both the drift and diffusion components are required to be considered for an accurate drain current. The concept of the gradient in the quasi-Fermi level is a convenient way to do so. In this work, a pseudo 2D potential profile which takes into account the vertical field due to the gate and the lateral field due to the source and drain junctions in addition to the difference in the flat-band voltage along the channel is used. Moreover, the mobility and the effective conduction layer depth used are also position dependent since the channel doping varies along the channel. Model predictions are compared with the results predicted by the 2D numerical device simulator DESSIS, and a very good agreement between the two are observed.     

Observer-based dissipative control for Markovian jump systems via delta operators

This paper addresses the issue of observer-based dissipative control problem for a class of Markovian jump systems with random delay via delta operator approach. First, based on the construction of a novel Lyapunov functional together with the use of free-weighting matrix approach, a new set of sufficient conditions is established which ensures the stochastic asymptotic stability and dissipativity of the closed-loop augmented Markovian jump delta operator system. Next, the result is extended to design an observer-based state feedback dissipative control law such that the resulting closed-loop system is stochastically asymptotically stable with the desired dissipative performance index. Further, the existence of control laws is formulated in the form of linear matrix inequalities (LMIs) which can be easily solved by using some standard numerical packages. Also, the observer and control gains can be calculated by using the solutions of an obtained set of LMIs. It is worth pointing out that the dissipative control problem considered here includes the H_∞ and passivity-based control problems as special cases. Finally, two numerical examples with simulation are presented to demonstrate the effectiveness of the obtained design technique.