FDTD based transition time dependent crosstalk analysis for coupled RLC interconnects

The performance of high density chips operating in the GHz range is mostly affected by on-chip interconnects. The interconnect delay depends on many factors, a few of them are inputs toggling patterns, line ＆ coupling parasitics, input rise/fall time and source/load characteristics. The transition time of the input is of prime importance in high speed circuits. This paper addresses the FDTD based analysis of transition time effects on functional and dynamic crosstalk. The analysis is carried out for equal and unequal transition times of coupled inputs. The analysis of the effects of unequal rise time is equally important because practically, it is quite common to have mismatching in the rise time of the signals transmitting through different length wires. To demonstrate the effects, two distributed RLC lines coupled inductively and capacitively are taken into consideration. The FDTD technique is used because it gives accurate results and carries time domain analysis of coupled lines. The number of lumps in SPICE simulations is considered the same as those of spatial segments. To validate the FDTD computed results, SPICE simulations are run and results are compared. A good agreement of the computed results has been observed with respect to SPICE simulated results. An average error of less than 3.2% is observed in the computation of the performance parameters using the proposed method.

Propagation delay and power dissipation for different aspect ratio of single-walled carbon nanotube bundled TSV

Through-silicon vias （TSVs） have provided an attractive solution for three-dimensional （3D） integrated devices and circuit technologies with reduced parasitic losses and power dissipation, higher input-output （I/O） den- sity and improved system performance. This paper investigates the propagation delay and average power dissipation of single-walled carbon nanotube bundled TSVs having different via radius and height. Depending on the physical configuration, a comprehensive and accurate analytical model of CNT bundled TSV is employed to represent the via （vertical interconnect access） line of a driver-TSV-load （DTL） system. The via radius and height are used to estimate the bundle aspect ratio （AR） and the cross-sectional area. For a fixed via height, the delay and the power dissipation are reduced up to 96.2% using a SWCNT bundled TSV with AR = 300 ： 1 in comparison to AR = 6：1.

FDTD technique based crosstalk analysis of bundled SWCNT interconnects

The equivalent electrical circuit model of a bundled single-walled carbon nanotube based distributed RLC interconnects is employed for the crosstalk analysis. The accurate time domain analysis and crosstalk effect in the VLSI interconnect has emerged as an essential design criteria. This paper presents a brief description of the numerical method based finite difference time domain （FDTD） technique that is intended for estimation of voltages and currents on coupled transmission lines. For the FDTD implementation, the stability of the proposed model is strictly restricted by the Courant condition. This method is used for the estimation of crosstalk induced propagation delay and peak voltage in lossy RLC interconnects. Both functional and dynamic crosstalk effects are analyzed in the coupled transmission line. The effect of line resistance on crosstalk induced delay, and peak voltage under dynamic and functional crosstalk is also evaluated. The FDTD analysis and the SPICE simulations are carried out at 32 nm technology node for the global interconnects. It is observed that the analytical results obtained using the FDTD technique are in good agreement with the SPICE simulation results. The crosstalk induced delay, propagation delay, and peak voltage obtained using the FDTD technique shows average errors of 4.9%, 3.4% and 0.46%, respectively, in comparison to SPICE.

Tapered Optical Fiber-Based LSPR Biosensor for Ascorbic Acid Detection

The ascorbic acid(AA)is a biomarker that can be used to detect the symptoms of severe disorders such as scurvy,Parkinson’s,Alzheimer’s,and cardiovascular diseases.In this work,a simple and effective sensor model is developed to diagnose the presence of AA samples.To develop the sensor,a tapered single-mode optical fiber has been used with the well-known phenomenon of localized surface plasmon resonance(LSPR).For LSPR,the tapered region is immobilized with synthesized gold nanoparticles(AuNPs)and zinc oxide nanoparticles(ZnO-NPs)whose absorbance peak wavelengths appear at 519nm and 370nm,respectively.On the basis of nanoparticles(NPs)configurations,two different biosensor probes are developed.In the first one,the sensing region is immobilized with AuNPs and named Probe I.In the second probe,the immobilized layer of AuNPs is further coated with a layer of ZnO-NPs,and a resultant probe is termed as Probe II.The characterizations of synthesized AuNPs and developed fiber probes are done by the ultraviolet-visible(UV-vis)spectrophotometer,high-resolution transmission electron microscope(HR-TEM),atomic force microscopy(AFM),and scanning electron microscope(SEM).To enhance the selectivity,a sensing region of probes is functionalized with ascorbate oxidase enzyme that oxidizes the AA in the presence of oxygen.The response of developed sensor probes is authenticated by sensing the samples of AA in the range from 500 nM to 1 mM,which covers the range of AA found in human bodies,i.e.,40μM-120μM.The performance analysis of the developed sensor probes has been done in terms of their stability,reproducibility,reusability,and selectivity.To observe the stability of AA,a pH-test has also been done that results in a better solubility of AA molecules in phosphate-buffered saline(PBS)solution.