This document discusses reliability evaluation of combinational circuits using the NFAS reliability analysis tool. The tool was used to evaluate single event transients (SETs) in three combinational logic cells from a 45nm standard cell library. Experiments examined the effects of operating frequency, technology node, SET characteristics, and linear energy transfer on propagated faults. Results showed propagated faults increasing with higher frequency and linear energy transfer, and decreasing with more advanced technology nodes. The NFAS tool provides useful information for developing more robust and efficient fault tolerant techniques.

1. Grupo de Sistemas Digitais e Embarcados (GSDE)
www.gsde.furg.br
SIM 2016
31st
South Symposium on Microelectronics
Porto Alegre, Brazil
Reliability Evaluation of Combinational Circuits from a
Standard Cell Library
Ygor Quadros de Aguiar, Alexandra Lackmann Zimpeck, Cristina Meinhardt

2. 2/30
31st
South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Agenda
1. Introduction
2. Motivation and Objective
3. Single Event Effects
4. NFAS-tool
5. Experiments
6. Final Remarks

3. 3/30
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South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Introduction
New challenges introduced by
tecnology scaling:
❖ process variability
❖ reliability
✓ increased device failure rates
✓ low yield

4. 4/30
31st
South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Motivation
The increasingly need of EDA (Electronic Design Automation) tools for:
✓ robustness evaluation of design
✓ assessment of fault tolerant tecniques
The NFAS-tool
Stuck-On
Stuck-Open
Single Event Transient

5. 5/30
31st
South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Objective
Evaluate the SET effects on combinational circuits from a
Standard Cell Library to explore the features
designed at NFAS-tool (Nanotechnology Fault Analysis
Simulation tool)

6. Grupo de Sistemas Digitais e Embarcados (GSDE)
www.gsde.furg.br
Single Event Effects (SEE)

7. 7/30
31st
South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Single Event Effects (SEE):
Destructive:
SEL (Single Event Latchup), SEGR (Single Event Gate Rupture) ...
Non-destructive:
SET (Single Event Transient): combinational cells
SEU (Single Event Upset): sequential cells
Fig. Single Event Upset (SEU) and Single Event Transient (SET) (Azambuja J. R., 2014)

8. 8/30
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South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Single Event Transient (SET)
Figura: Schematic of energy transfer as a voltage pulse (Wang, 2008)

9. 9/30
31st
South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Single Event Transient (SET)
Figura: Schematic of energy transfer as a voltage pulse (Wang, 2008)
Linear Energy Transfer:
amount of energy released
by a particle per unit
length crossed

10. Grupo de Sistemas Digitais e Embarcados (GSDE)
www.gsde.furg.br
NFAS-tool

11. 11/30
31st
South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Injection of Transient Faults
NFAS-tool
Circuit Parameters
Fault Parameters
Netlist File
NGSpice
Netlist under faults
Fault Analysis/
Log Files
Output Files from
electrical simulations
(.data)

12. 12/30
31st
South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Interface - SET Injections

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South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Reliability Analysis
- Modelo da falha SET
- Inserção de Fonte de Corrente

14. Grupo de Sistemas Digitais e Embarcados (GSDE)
www.gsde.furg.br
Experiments for SET injections

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South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Set of analysis available by the tool:
✓ influence of operating frequency;
✓ different technologies node;
✓ different SET characteristics;
✓ reliability regarding the input vectors.
Reliability Analysis

16. 16/30
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South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Experiments
❖ Fault injection carried on the output nodes.
➢ worst scenario
❖ Number of faults: two injections for each circuit time slot of simulation
➢ HA_X1: 22 injections,
➢ AOI21_X1: 26 injections,
➢ NAND2_X1: 12 injections.
❖ 3 combinational logic cells from a 45nm commercial Standard Cell library:

17. 17/30
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South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Experiments

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South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Operating Frequency Analysis
Technology node: 45nm High Performance PTM and LET = 1 MeV-cm2
/mg
PropagatedFaults(%)

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South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
PropagatedFaults(%)
Operating Frequency Analysis
Technology node: 45nm High Performance PTM and LET = 3 MeV-cm2
/mg

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South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Technology Node Analysis
PropagatedFaults(%)Half Adder (HA_X1) and LET = 1 MeV-cm2
/mg

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South Symposium on Microelectronics
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~15%
>30%
PropagatedFaults(%)
Technology Node Analysis
Half Adder (HA_X1) and LET = 1 MeV-cm2
/mg

22. 22/30
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South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
PropagatedFaults(%)
Technology Node Analysis
2-input NAND (NAND2_X1) and LET = 1 MeV-cm2
/mg

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South Symposium on Microelectronics
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~35%
~41,67%
PropagatedFaults(%)
Technology Node Analysis
2-input NAND (NAND2_X1) and LET = 1 MeV-cm2
/mg

24. 24/30
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Porto Alegre, Brazil – May/2016www.gsde.furg.br
Analysis of Linear Energy Transfer
Propagated Faults (%)

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South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Propagated Faults (%)
Analysis of Linear Energy Transfer

26. 26/30
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South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Propagated Faults (%)
Analysis of Linear Energy Transfer

27. 27/30
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South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Propagated Faults (%)
Analysis of Linear Energy Transfer
~3X

28. Grupo de Sistemas Digitais e Embarcados (GSDE)
www.gsde.furg.br
Final Remarks

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South Symposium on Microelectronics
Porto Alegre, Brazil – May/2016www.gsde.furg.br
Increased need for EDA tools regarding reliability analysis!!
NFAS-tool
✓ evaluates the reliability of combinational logic circuits under SET faults
✓ provides a set of information about the behavior of the faulty circuit elucidating the
direct influence of design parameters
✓ supports the development of fault tolerant techniques more robust and efficient
Final Remarks

30. Grupo de Sistemas Digitais e Embarcados (GSDE)
www.gsde.furg.br
SIM 2016
31st
South Symposium on Microelectronics
Porto Alegre, Brazil
Reliability Evaluation of Combinational Circuits from a
Standard Cell Library
Ygor Quadros de Aguiar
ygoraguiar@furg.br