sill torres, bastos: mbbics robust modular bulk built-in current sensors for detection of transient...

Sill Torres, Bastos: mBBICS

Robust Modular Bulk Built-In Current Sensors for Detection of Transient Faults

Frank Sill Torres+, Rodrigo Possamai Bastos*

+ Department of Electronic Engineering, Federal

University of Minas Gerais, Belo Horizonte, Brazil

* LIRMM, Université Montpellier II / CNRS UMR 5506

Montpellier, France

2Sill Torres, Bastos: mBBICS

Preliminaries

Modular Bulk Built-In Current Sensors

Results

Conclusion

OutlineOutline


+++ +-

-

--

PreliminariesPreliminariesTransient-Faults in Integrated Circuits (IC)

n+

p

n+

Charged Charged particle particle

ISET

out = 1out = 1 0 0in = 0in = 0 out = 1out = 1

Increasing susceptibility of CMOS IC to radiation effects due to

decreasing technology sizes

Environmental (α-particles, neutrons, …) and intentional (laser

beams, …) sources

► Can cause transition faults


Redundancy (Time, Logic)

– Well known approach

– Strong increase in area, power and/or

delay

Shadow Latches (Razor)

– Moderate area increase

– Useless against long-duration TF

Built-In Current Sensors (BICS)

– Good for Memory block

– Not appropriate for logic

PreliminariesPreliminariesSolutions for Transient Fault Detection

V

Δ

CMPCMP

BICS


At particle strikes transistor in off mode → generation of current

between transistor’s reverse-biased drain-bulk pn-junction

Idea: Current sensor between Bulk and ground → Bulk BICS (BBICS)

PreliminariesPreliminariesBulk Built-In Current Sensors

inin outout

PMOS-BBICS

Flag_P

pmos_bulkpmos_bulk

…

Flag_N

nmos_bulknmos_bulk

…NMOS-BBICS

Neto, Micro, 26/5, p. 10, 2006

IBIB IA

IA


Modular Bulk Built-In Current SensorsModular Bulk Built-In Current SensorsOrigination of Approach

High area effort Strong susceptibility to parameter / temperature variations Offset on bulk voltage → increased leakage (sub-threshold) of

monitored circuits

High area effort Strong susceptibility to parameter / temperature variations Offset on bulk voltage → increased leakage (sub-threshold) of

monitored circuits

Common problems of existing Bulk-BICS

Functionality sharing (reduction of power/area) Bulk connected directly with VDD/GND via a high ohmic

transistor (as proposed in “Wirth, in Mic. Rel., v.48/5, 2008”) Implementation of positive feedback structure (increase of

stability / decrease of sensor response time)

Functionality sharing (reduction of power/area) Bulk connected directly with VDD/GND via a high ohmic

transistor (as proposed in “Wirth, in Mic. Rel., v.48/5, 2008”) Implementation of positive feedback structure (increase of

stability / decrease of sensor response time)

Proposed solution


Modular Bulk Built-In Current SensorsModular Bulk Built-In Current SensorsArchitecture (only NMOS)

TailHead 1Head 2


Modular Bulk Built-In Current SensorsModular Bulk Built-In Current SensorsMode of Operation (NMOS)

1. Particle Strike

2. Current through

Nh1 → voltage

peak on bulkNMOS

3. Nh2 starts to

conduct → voltage

drop on headNMOS

4. State of invout

changes → pos.

feedback

5. Error flag set

reset

errorNMOS

head n tail

Nh1 Nh2

Pt3

INV3

Pt1

Nt1

bulkNMOS 1

BUT n

...

Pt2

Nt2

inv o

ut

headNMOS

reset

errorNMOS

head n tail

Nh1

Nh2

Pt3

INV3

Pt1

Nt1

bulkNMOS 1

BUT n

...

Pt2

Nt2

inv o

ut

headNMOS

R

reset

errorNMOS

head n tail

Nh1 Nh2

Pt3

INV3

Pt1

Nt1

bulkNMOS 1

BUT n

...

Pt2

Nt2

inv o

ut

headNMOS

reset

errorNMOS

head n tail

Nh1 Nh2

Pt3

INV3

Pt1

Nt1

bulkNMOS 1

BUT n

...

Pt2

Nt2

inv o

ut

headNMOS

reset

errorNMOS

head n tail

Nh1 Nh2

Pt3

INV3

Pt1

Nt1

bulkNMOS 1

BUT n

...

Pt2

Nt2

inv o

ut

headNMOS


ResultsResultsSimulation Environment

TailPMOS

Group 1

HeadPMOS 1Group 1

HeadPMOS 2 Group 1

HeadNMOS 2 HeadNMOS 2

TailNMOSTailNMOS

HeadNMOS 1 HeadNMOS 1

ErrorNMOS

HeadPMOS 1 Group 2

ErrorPMOS 2TailPMOS

Group 2

HeadPMOS 2 Group 2

ErrorPMOS 1

BUT 2 BUT 2 BUT 1BUT 1

BUT (Block Under Test): 6 chains of 10 inverter

2 groups of PMOS mBBICS (load equalization w/ NMOS mBBICS)

Particle strike via current source connected to 5th inverter of 1st chain

Predictive 16 nm technology (Bulk CMOS, Berkeley)

Ifault


ResultsResultsDetection Capability (6 Heads, nominal case)

PMOS NMOS

Qftf

(tr = 1ps)tresp tresp

1 fC 5 ps - -2 fC 5 ps 452 ps 430 ps3 fC 5 ps 136 ps 76 ps4 fC 5 ps 89 ps 50 ps1 fC 10 ps - -2 fC 10 ps 270 ps 210 ps3 fC 10 ps 78 ps 62 ps4 fC 10 ps 55 ps 43 ps1 fC 20 ps - -2 fC 20 ps 210 ps 175 ps3 fC 20 ps 81 ps 70 ps4 fC 20 ps 55 ps 50 ps

‑ no TF no detection

‑ no TF detection

‑ TF detection

- TFno detection

TF – Transient Fault, tresp – Sensor Response Time


ResultsResultsInfluence of Heads Amount (Nominal Models, Qf = 2 fC, tf = 5 ps)

0%

10%

20%

30%

40%

50%

60%

0 ps

200 ps

400 ps

600 ps

800 ps

1 4 7 10 13 16 19 22

Area

off

set

Resp

onse

tim

e

Nº heads

tresp (PMOS) tresp (NMOS) Area offset


ResultsResultsTemperature Analysis (Nominal Models, Qf = 2 fC, tf = 5 ps)

0 ps

200 ps

400 ps

600 ps

800 ps

1000 ps

-20 °C 0 °C 20 °C 40 °C 60 °C 80 °C

Resp

onse

tim

e

TemperaturePMOS NMOS


ResultsResultsMonte Carlo Analysis (tf = 5 ps)

0 ps

200 ps

400 ps

600 ps

800 ps

1000 ps

1200 ps

1 fC 2 fC 3 fC 4 fC

Max

imum

resp

onse

tim

e

Collected Charge Qf

PMOS NMOS


Bulk Built-In Current Sensors (BBICS) promising solution to detect

soft errors in current CMOS technologies

Main problems: susceptibility to variations, area, power

Proposed modular BBICS (mBBICS) combines functional block

sharing and positive feedback

Simulations (16 nm PTM)

– All injected transition faults detected for nominal and MonteCarlo

(MC) case

– Max. response times of ca. 500 ps (nominal) and ca. 1 ns (MC)

– Area offset of 25 %

– Very low increase in power dissipation

ConclusionsConclusions


Thank you!

[email protected]@lirmm.fr

OptMAlab / ARTwww.asic-reliability.com

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