scholarly journals Design and Analysis of Soft Error Rate in FET/CNTFET Based Radiation Hardened SRAM Cell

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 33
Author(s):  
Bharathi Raj Muthu ◽  
Ewins Pon Pushpa ◽  
Vaithiyanathan Dhandapani ◽  
Kamala Jayaraman ◽  
Hemalatha Vasanthakumar ◽  
...  
Keyword(s):  
Soft Errors ◽  
Memory Cell ◽  
Soft Error ◽  
Access Time ◽  
Electronic Systems ◽  
Memory Cells ◽  
Noise Margin ◽  
Sram Cell ◽  
Driver Circuit ◽  
Radiation Hardened

Aerospace equipages encounter potential radiation footprints through which soft errors occur in the memories onboard. Hence, robustness against radiation with reliability in memory cells is a crucial factor in aerospace electronic systems. This work proposes a novel Carbon nanotube field-effect transistor (CNTFET) in designing a robust memory cell to overcome these soft errors. Further, a petite driver circuit to test the SRAM cells which serve the purpose of precharge and sense amplifier, and has a reduction in threefold of transistor count is recommended. Additionally, analysis of robustness against radiation in varying memory cells is carried out using standard GPDK 90 nm, GPDK 45 nm, and 14 nm CNTFET. The reliability of memory cells depends on the critical charge of a device, and it is tested by striking an equivalent current charge of the cosmic ray’s linear energy transfer (LET) level. Also, the robustness of the memory cell is tested against the variation in process, voltage and temperature. Though CNTFET surges with high power consumption, it exhibits better noise margin and depleted access time. GPDK 45 nm has an average of 40% increase in SNM and 93% reduction of power compared to the 14 nm CNTFET with 96% of surge in write access time. Thus, the conventional MOSFET’s 45 nm node outperforms all the configurations in terms of static noise margin, power, and read delay which swaps with increased write access time.

scholarly journals VARIABILITY ANALYSIS OF 6T AND 7T SRAM CELL IN SUB-45NM TECHNOLOGY

2011 ◽  
Vol 12 (1) ◽  
pp. 13-30 ◽  
Author(s):  
Aminul Islam ◽  
Mohd. Hasan
Keyword(s):  
Random Access ◽  
Memory Cell ◽  
Static Random Access Memory ◽  
Access Time ◽  
Access Memory ◽  
Static Noise Margin ◽  
Noise Margin ◽  
Sram Cell ◽  
Pvt Variations ◽  
Static Noise

This paper analyses standard 6T and 7T SRAM (static random access memory) cell in light of process, voltage and temperature (PVT) variations to verify their functionality and robustness. The 7T SRAM cell consumes higher hold power due to its extra cell area required for its functionality constraint. It shows 60% improvement in static noise margin (SNM), 71.4% improvement in read static noise margin (RSNM) and 50% improvement in write static noise margin (WSNM). The 6T cell outperforms 7T cell in terms of read access time (TRA) by 13.1%. The write access time (TWA) of 7T cell for writing "1" is 16.6 x longer than that of 6T cell. The 6T cell proves it robustness against PVT variations by exhibiting narrower spread in TRA (by 1.2 x) and Twa (by 3.4x). The 7T cell offers 65.6% saving in read power (RPWR) and 89% saving in write power (WPWR). The RPWR variability indicates that 6T ell is more robust against process variation by 3.9x. The 7T cell shows 1.3x wider write power (WPWR) variability indicating 6T cell's robustness against PVT variations. All the results are based on HSPICE simulation using 32 nm CMOS Berkeley Predictive Technology Model (BPTM).

scholarly journals Bias Temperature Instability Aware and Soft Error Tolerant Radiation Hardened 10T SRAM Cell

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 256 ◽  
Author(s):  
Ambika Prasad Shah ◽  
Michael Waltl
Keyword(s):  
Soft Error ◽  
Critical Charge ◽  
Bias Temperature Instability ◽  
Noise Margin ◽  
Sram Cell ◽  
Radiation Hardened ◽  
The Stability ◽  
A Charge ◽  
The Impact ◽  
Static Noise

In this paper, we propose an asymmetric radiation-hardened 10T (AS10T) SRAM cell and analyze the impact of bias temperature instabilities (BTI) on the single event upset of the modified structure. For this, we make use of a read decoupled circuit to improve the stability of the reading cycle, and a charge booster circuit to increase the critical charge at the sensitive node of the SRAM cell. First, we compare the noise margin of several reference cells and can clearly observe that the read static noise margin (RSNM) of AS10T is 3.25× higher than as can be achieved for the 6T SRAM cell. This improvement is due to the read decoupled path used for the read operation. To analyze the soft-error hardening, we calculate the critical charge and observe that the critical charge of the proposed AS10T cell exceed the same parameter of other SRAM cells. Further, we perform critical charge simulations and stability analysis considering BTI and observe that the AS10T SRAM cell is also less affected by BTI as the reference cells.

Design of Low Power Half Select Free 10T Static Random-Access Memory Cell

2020 ◽  
pp. 2150073 ◽  
Author(s):  
Ashish Sachdeva ◽  
V. K. Tomar
Keyword(s):  
Random Access ◽  
Memory Cell ◽  
Random Access Memory ◽  
Static Random Access Memory ◽  
Access Time ◽  
Signal To Noise ◽  
Access Memory ◽  
Noise Margin ◽  
Sram Cell ◽  
Power Delay Product

This paper presents a circuit-level technique of designing a low power and half select free 10T Static Random-Access Memory Cell (SRAM). The proposed cell works with single end read operation and differential write operation. The proposed bit-cell is free from half select issue and supports bit interleaving format. The presented 10T cell exhibits 40.75% lower read power consumption in comparison to conventional 6T SRAM cell, attributed to reduction of activity factor during read operation. The loop cutting transistors used in core latch improve write signal-to-noise margin (WSNM) by 14.94% and read decoupled structure improve read signal-to-noise margin (RSNM) by [Formula: see text] as compared to conventional 6T SRAM. In the proposed work, variability analysis of significant design parameters such as read current, stand-by SNM, and read power of the projected 10T SRAM cell is presented and compared with considered topologies. Mean value of hold static noise margin of the cell for 3000 samples is [Formula: see text] times higher than the considered D2p11T cell. The proposed 10T cell shows [Formula: see text] and [Formula: see text] narrower read access time and write access time, respectively, as compared to conventional 6T SRAM cell. Read current to bit-line leakage current ratio of the proposed 10T cell has been investigated and is improved by [Formula: see text] as compared to conventional 6T SRAM cell. The write power delay product and read power delay product of the proposed 10T cell are [Formula: see text] and [Formula: see text] lower than conventional 6T SRAM cell. In this work, cadence virtuoso tool with Generic Process Design Kit (GPDK) 45[Formula: see text]nm technology file has been utilized to carry out simulations.

scholarly journals A sensing circuit for single-ended read-ports of SRAM cells with bit-line power reduction and access-time enhancement

2011 ◽  
Vol 9 ◽  
pp. 247-253 ◽  
Author(s):  
T. Heselhaus ◽  
T. G. Noll
Keyword(s):  
Threshold Voltage ◽  
Power Reduction ◽  
Access Time ◽  
Memory Cells ◽  
Charge Voltage ◽  
Voltage Level ◽  
Noise Margin ◽  
Sram Cell ◽  
Ground Line ◽  
Line Noise

Abstract. The conventional sensing scheme of single-ended read-only-ports as integrated in 8T-SRAM cells suffers from low performance compared to double-ended complementary sensing schemes. In the proposed sensing scheme the pre-charge voltage of the single-ended read-bit-line is set to a level above the threshold voltage of the sensing device with an adjustable margin. This margin is minimized to speed up the read access on the one hand and kept large enough to provide a sufficient bit-line noise margin on the other hand. The pre-charge voltage level of the proposed sensing circuit tracks the threshold voltage of the sensing device under process variations in order to maintain a minimum required bit-line noise margin. To avoid unnecessary bit-line discharging, the proposed sensing scheme employs a modified 8T-SRAM cell. Compared to the conventional 8T-SRAM cell, the read port of the proposed cell provides a virtual ground line running in parallel to the bit-lines. An internal driver of the sensing circuit releases the virtual ground line during the evaluation period to prevent the charge dissipation resulting in a raised voltage level. The reduced pre-charge level and the increased virtual ground lead to a reduced bit-line voltage swing and thus a bit-line power reduction. Access time, energy dissipation, and noise margin of the proposed sensing circuit are compared with conventional sensing circuits from the literature for different numbers of memory cells connected to the bit-line. It is shown, that for a specific number of memory cells per bit-line the proposed circuit achieves fastest access time at low power operation.

The Combined Effects of Cycling Endurance and TID on Floating Gate Memory Cells

2021 ◽  
Author(s):  
Side Song ◽  
Guozhu Liu ◽  
Qi He ◽  
Xiang Gu ◽  
Genshen Hong ◽  
...  
Keyword(s):  
Radiation Effects ◽  
Memory Cell ◽  
Floating Gate ◽  
Combined Effects ◽  
Memory Cells ◽  
Threshold Voltage Shift ◽  
Floating Gate Memory ◽  
Interface Generation ◽  
Radiation Hardened ◽  
Radiation Induced

Abstract In this paper, the combined effects of cycling endurance and radiation on floating gate memory cell are investigated in detail, the results indicate that: 1.The programmed flash cells with a prior appropriate number of program and erase cycling stress exhibit much smaller threshold voltage shift than their counterpart in response to radiation, which is mainly ascribed to the recombination of trapped electrons (introduced by cycling stress) and trapped holes (introduced by irradiation) in the oxide surrounding the floating gate; 2.The radiation induced transconductance degradation in prior cycled flash cell is more severe than those without cycling stress in both of the programmed state and erased state; 3. Radiation is more likely to induce interface generation in programmed state than in erased state. This paper will be useful in understanding the issues involved in cycling endurance and radiation effects as well as in designing radiation hardened floating gate memory cells.

Design of Low Power with Expanded Noise Margin Subthreshold 12T SRAM Cell for Ultra-Low Power Devices

2020 ◽  
pp. 2150106
Author(s):  
Harekrishna Kumar ◽  
V. K. Tomar
Keyword(s):  
Power Dissipation ◽  
Random Access ◽  
Memory Cell ◽  
Random Access Memory ◽  
Static Random Access Memory ◽  
Access Time ◽  
Access Memory ◽  
Subthreshold Region ◽  
Noise Margin ◽  
Static Noise

In the proposed work, a differential write and single-ended read half-select free 12 transistors static random access memory cell is designed and simulated. The proposed cell has a considerable reduction in power dissipation with better stability and moderate performance. This cell operates in subthreshold region and has a higher value of read static noise margin as compared to conventional six transistors static random access memory cell. A power cut-off technique is utilized between access and pull-up transistors during the write operation. It results in an increase in write static noise margin as compared to all considered cells. In the proposed cell, read and write access time is improved along with a reduction in read/write power dissipation as compared to conventional six transistors static random access memory cell. The bitline leakage current in the proposed cell is reduced which improves the [Formula: see text] ratio of the cell under subthreshold region. The proposed cell occupies less area as compared to considered radiation-hardened design 12 transistors static random access memory cell. The computed electrical quality metric of proposed cell is better among considered static random access memory cells. Process variation analysis of read stability, access time, power dissipation, read current and leakage current has been performed with the help of Monte Carlo simulation at 3,000 points to get more soundness in the results. All characteristics of static random access memory cells are compared at various supply voltages.

Design of a Stable Low Power 11-T Static Random Access Memory Cell

2020 ◽  
Vol 29 (13) ◽  
pp. 2050206 ◽  
Author(s):  
Ashish Sachdeva ◽  
V. K. Tomar
Keyword(s):  
Random Access ◽  
Memory Cell ◽  
Random Access Memory ◽  
Static Random Access Memory ◽  
Signal To Noise ◽  
Access Memory ◽  
Noise Margin ◽  
Sram Cell ◽  
Variation Tolerance ◽  
Read Signal

In this paper, a 11-T static random-access memory (SRAM) cell has been examined that shows a fair reduction in read power dissipation while upholding the stability and moderate performance. In the presented work, parametric variability analysis of various design metrices such as signal to noise margin, read current and read power of the Proposed 11T cell are presented and compared with few considered topologies. The Proposed cell offers single ended write operation and differential read operation. The improvement in read signal to noise margin and write signal to noise margin with respect to conventional 6T SRAM is 10.63% and 33.09%, respectively even when the write operation is single ended. Mean hold static noise margin of the cell for 3000 samples is [Formula: see text] times higher than considered D2p11T cell. Sensitivity analysis of data retention voltage (DRV) with respect to temperature variations is also investigated and compared with considered topologies. DRV variation with temperature is least in FF process corner. In comparison to conventional 6T SRAM cell, the write and read delay of Proposed 11T cell gets improved by [Formula: see text] and 1.64%, respectively. Proposed 11T topology consumes least read energy in comparison with considered topologies. In comparison with another considered 11T topology, i.e., D2p11T cell, Proposed cell consumes 13.11% lesser area. Process variation tolerance with Monte Carlo simulation for read current and read power has been investigated using Cadence virtuoso tool with GPDK 45-nm technology.

scholarly journals A Technique for Designing Variation Resilient Subthreshold Sram Cell

2013 ◽  
Vol 14 (1) ◽  
Author(s):  
Aminul Islam
Keyword(s):  
Process Variations ◽  
Access Time ◽  
Static Noise Margin ◽  
Design Metrics ◽  
Random Dopant Fluctuation ◽  
Noise Margin ◽  
Sram Cell ◽  
Transmission Gates ◽  
The Cost ◽  
Static Noise

This paper presents a technique for designing a variability aware subthreshold SRAM cell. The architecture of the proposed cell is similar to the standard read-decoupled 8-transistor (RD8T) SRAM cell with the exception that the access FETS are replaced with transmission gates (TGs). In this work, various design metrics are assessed and compared with RD8T SRAM cell. The proposed design offers 2.14× and 1.75× improvement in TRA (read access time) and TWA (write access time) respectively compared with RD8T. It proves its robustness against process variations by featuring narrower spread in TRA distribution (2.35×) and TWA distribution (3.79×) compared with RD8T. The proposed bitcell offers 1.16× higher read current (IREAD) and 1.64× lower bitline leakage current (ILEAK) respectively compared with RD8T. It also shows its robustness by offering 1.34× (1.58×) tighter spread in IREAD (ILEAK) compared with RD8T. It exhibits 1.42× larger IREAD to ILEAK ratio. It shows 2.2× higher frequency @ 250 mV with read bitline capacitance of 10 fF. Besides, the proposed bitcell achieves same read stability and write-ability as that of RD8T at the cost of 3 extra transistors. The leakage power of the proposed design is close to that of RD8T.   ABSTRAK: Kertas kerja ini membentangkan teknik merekabentuk sel bawah ambang SRAM yang bolehubah. Senibina sel yang dicadangkan adalah sama dengan sel SRAM 8-transistor (RD8T) “pisahan-bacaan” piawai kecuali FET akses  digantikan dengan sel pintu transmisi (TGs). Di dalam kajian ini, beberapa metrik rekabentuk dinilai dan dibandingkan dengan sel RD8T SRAM. Rekabentuk yang dicadangkan menawarkan  peningkatan 2.14× dan 1.75×  dalam TRA (masa akses baca) dan TWA (masa akses tulis) berbanding dengan RD8T. Ia membuktikan kekukuhan variasi proses dengan menampilkan tebaran yang lebih sempit dalam pengagihan TRA (2.35 ×) dan pengagihan TWA (3.79 ×) berbanding dengan RD8T. Sel-Bit yang dicadangkan mempunyai arus baca 1.16 × lebih tinggi  (IREAD) dan arus bocor bitline 1.64 × lebih rendah (ILEAK) berbanding dengan RD8T. Ia juga membuktikan kekukuhan dengan menawarkan 1.34 × (1.58 ×) penyebaran sempit di IREAD (ILEAK) berbanding dengan RD8T dan nisbah IREAD / ILEAK 1.42 × lebih besar. Ia menunjukkan kekerapan 2.2 × lebih tinggi pada 250 mV dengan kemuatan membaca bitline sebanyak 10 fF. Selain itu, sel bit yang dicadangkan mencapai kestabilan membaca dan keupayaan menulis yang sama seperti RD8T dengan kos tambahan 3 transistor. Kebocoran kuasa  rekabentuk yang dicadangkan hampir sama dengan RD8T. KEYWORDS: variability; robust, subthreshold; random dopant fluctuation (RDF); read static noise margin (RSNM); write static noise margin (WSNM).

scholarly journals FinFET SRAM cell with improved stability and power for low power applications.

2019 ◽  
Vol 14 (2) ◽  
pp. 1-8
Author(s):  
Shilpi Birla
Keyword(s):  
Memory Cell ◽  
Static Noise Margin ◽  
Noise Margin ◽  
Sram Cell ◽  
Improved Stability ◽  
Cell Stability ◽  
Subthreshold Voltage ◽  
The Stability ◽  
Subthreshold Operation ◽  
Static Noise

In this paper, a new 11T SRAM cell using Double gate FET (FinFET technology) has been proposed, cell basic component is the 6T SRAM cell with 4 NMOS access transistors to improve the stability over CMOSFET circuits and also makes it a dual port memory cell. The proposed cell also used a header scheme in which one extra PMOS transistor is used which is biased at different voltages to improve the read and write stability which helps in reducing the leakage current, active power. The cell shows improvement in RSNM (Read Static Noise Margin) with LP8T by 2.39x at threshold and subthreshold voltage 2.68x with D6T SRAM cell, 5.5x with TG8T. The WSNM (Write Static Noise Margin) and HM (Hold Margin) of the SRAM cell at 0.9V is 306mV and 384mV.At subthreshold operation also, it shows improvement. The Leakage power reduced by 0.125x with LP8T, 0.022x with D6T SRAM cell, TG8T and SE8T. Impact of process variation on cell stability also been analyzed.

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