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Lehrstuhl für Technische Elektronik Technische Universität München MOS-AK/GSA Workshop, April 11-12, 2013, Munich Modeling Effects of Dynamic BTI Degradation on Analog and Mixed-Signal CMOS Circuits Leonhard Heiß , Cenk Yilmaz, Christoph Werner, Doris Schmitt-Landsiedel Contact: [email protected] Lehrstuhl f¨ ur Technische Elektronik Prof. Doris Schmitt-Landsiedel Technische Universit¨ at M¨ unchen

Modeling Effects of Dynamic BTI Degradation on Analog and ... · Lehrstuhl für Technische Elektronik Technische Universität München MOS-AK/GSA Workshop, April 11-12, 2013, Munich

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Lehrstuhl für Technische Elektronik Technische Universität München

MOS-AK/GSA Workshop, April 11-12, 2013, Munich

Modeling Effects of Dynamic BTI Degradation on Analog andMixed-Signal CMOS Circuits

Leonhard Heiß, Cenk Yilmaz, Christoph Werner, Doris Schmitt-Landsiedel

Contact: [email protected]

Lehrstuhl fur Technische ElektronikProf. Doris Schmitt-LandsiedelTechnische Universitat Munchen

Lehrstuhl für Technische Elektronik Technische Universität München

Lehrstuhl fur Technische Elektronik

Head: Prof. Doris Schmitt-Landsiedel

12 PhD Students and Research Assistants

Circuit ReliabilityRobust/LP DesignNML

Digital CMOS

Timing Monitors

Adaptive VoltageScaling

AMS/RF CMOS

AgeingModeling/Simulation

Ageing Test Structures

Impact of Degradationon Circuit Performance

Nano Magnetic Logic

April 12th, 2013 2

Lehrstuhl für Technische Elektronik Technische Universität München

Content

1 Introduction and Motivation

2 Physical NBTI Model

3 New Simulation Method for NBTI in Analog CMOS Circuits

4 SC Comparator

5 SAR ADC

6 Conclusion and Outlook

7 References

April 12th, 2013 3

Lehrstuhl für Technische Elektronik Technische Universität München

Content

1 Introduction and Motivation

2 Physical NBTI Model

3 New Simulation Method for NBTI in Analog CMOS Circuits

4 SC Comparator

5 SAR ADC

6 Conclusion and Outlook

7 References

April 12th, 2013 4

Lehrstuhl für Technische Elektronik Technische Universität München

Introduction

NBTI: Negative Bias Temperature Instability:

Degradation of pMOSFETSMain impact: Increase of |Vth|

NBTI stress vs. NBTI relaxation:

Dynamic NBTI:

Sequence of stress/recovery phase causes fast changing ∆Vth(t)∆Vth(t) potential error source in high-precision analog circuits

April 12th, 2013 5

Lehrstuhl für Technische Elektronik Technische Universität München

Introduction

NBTI: Negative Bias Temperature Instability:

Degradation of pMOSFETSMain impact: Increase of |Vth|

NBTI stress vs. NBTI relaxation:

1. Stress:

Dynamic NBTI:

Sequence of stress/recovery phase causes fast changing ∆Vth(t)∆Vth(t) potential error source in high-precision analog circuits

April 12th, 2013 5

Lehrstuhl für Technische Elektronik Technische Universität München

Introduction

NBTI: Negative Bias Temperature Instability:

Degradation of pMOSFETSMain impact: Increase of |Vth|

NBTI stress vs. NBTI relaxation:

1. Stress: 2. Relaxation:

Static NBTI

Dynamic NBTI

Dynamic NBTI:

Sequence of stress/recovery phase causes fast changing ∆Vth(t)∆Vth(t) potential error source in high-precision analog circuits

April 12th, 2013 5

Lehrstuhl für Technische Elektronik Technische Universität München

Introduction

NBTI: Negative Bias Temperature Instability:

Degradation of pMOSFETSMain impact: Increase of |Vth|

NBTI stress vs. NBTI relaxation:

1. Stress: 2. Relaxation:

Static NBTI

Dynamic NBTI

Dynamic NBTI:

Sequence of stress/recovery phase causes fast changing ∆Vth(t)∆Vth(t) potential error source in high-precision analog circuits

April 12th, 2013 5

Lehrstuhl für Technische Elektronik Technische Universität München

Motivation

Starting point for our research:

State of the art reliability simulators do not include relaxation

Impact of relaxation on analog performance got hardly investigated

Sequence of stress/relaxation might cause circuit malfunction

Aim of our research:

1. Physical NBTI model, including relaxation

2. Integration of NBTI model into circuit simulator

3. Impact of relaxation on analog/mixed-signal circuits

4. Design of sophisticated test structures for analog circuits

April 12th, 2013 6

Lehrstuhl für Technische Elektronik Technische Universität München

Motivation

Starting point for our research:

State of the art reliability simulators do not include relaxation

Impact of relaxation on analog performance got hardly investigated

Sequence of stress/relaxation might cause circuit malfunction

Aim of our research:

1. Physical NBTI model, including relaxation

2. Integration of NBTI model into circuit simulator

3. Impact of relaxation on analog/mixed-signal circuits

4. Design of sophisticated test structures for analog circuits

April 12th, 2013 6

Lehrstuhl für Technische Elektronik Technische Universität München

Content

1 Introduction and Motivation

2 Physical NBTI Model

3 New Simulation Method for NBTI in Analog CMOS Circuits

4 SC Comparator

5 SAR ADC

6 Conclusion and Outlook

7 References

April 12th, 2013 7

Lehrstuhl für Technische Elektronik Technische Universität München

Recent Understanding and Modeling of NBTI

p+

n-Sub.

++

p+

++ + + + + + + + + ++ + + + + + + + + +

p++

SiO2

Stress Case:Charge capture increases |Vth|

Single defect:Capture time constant τc

p+

n-Sub.

++

p+

+

p++

+ +++ + +

SiO2

Relaxation Case:Charge emission decreases |Vth|again

Single Defect:Emission time constant τe

April 12th, 2013 8

Lehrstuhl für Technische Elektronik Technische Universität München

Capture and Emission Time Constants

τc and τe widely spreadDistribution modeled by 2 bivariate log-normal p.d.f’s [1]:

τc and τe temperature and bias dependentDistribution depends on: T ,VGS, CMOS technology

April 12th, 2013 9

Lehrstuhl für Technische Elektronik Technische Universität München

Markov Model for a single Defect Group

1 21: neutral state

2: positively charged

Defect group ( , ),

density within

Expectation value for threshold shift of single defect group:

|∆Vth(t)| ∝ dτe

τe + τc︸ ︷︷ ︸

a(VGS)

+(

|∆Vth(t0)| − dτe

τe + τc︸ ︷︷ ︸

a(VGS)

)

exp(

−( 1

τe+

1

τc︸ ︷︷ ︸

b(VGS)

)

t)

Bias dependence regarded by model parameters k1 and k2:

|∆Vth(t)| =(

k1VGS

)k2

a+(

|∆Vth(t0)| −(

k1VGS

)k2

a)

exp(

−bt)

April 12th, 2013 10

Lehrstuhl für Technische Elektronik Technische Universität München

Markov Model for a single Defect Group

1 21: neutral state

2: positively charged

Defect group ( , ),

density within

Expectation value for threshold shift of single defect group:

|∆Vth(t)| ∝ dτe

τe + τc︸ ︷︷ ︸

a(VGS)

+(

|∆Vth(t0)| − dτe

τe + τc︸ ︷︷ ︸

a(VGS)

)

exp(

−( 1

τe+

1

τc︸ ︷︷ ︸

b(VGS)

)

t)

Bias dependence regarded by model parameters k1 and k2:

|∆Vth(t)| =(

k1VGS

)k2

a+(

|∆Vth(t0)| −(

k1VGS

)k2

a)

exp(

−bt)

April 12th, 2013 10

Lehrstuhl für Technische Elektronik Technische Universität München

Markov Model for a single Defect Group

1 21: neutral state

2: positively charged

Defect group ( , ),

density within

Expectation value for threshold shift of single defect group:

|∆Vth(t)| ∝ dτe

τe + τc︸ ︷︷ ︸

a(VGS)

+(

|∆Vth(t0)| − dτe

τe + τc︸ ︷︷ ︸

a(VGS)

)

exp(

−( 1

τe+

1

τc︸ ︷︷ ︸

b(VGS)

)

t)

Bias dependence regarded by model parameters k1 and k2:

|∆Vth(t)| =(

k1VGS

)k2

a+(

|∆Vth(t0)| −(

k1VGS

)k2

a)

exp(

−bt)

April 12th, 2013 10

Lehrstuhl für Technische Elektronik Technische Universität München

Markov Model for a single Defect Group

1 21: neutral state

2: positively charged

Defect group ( , ),

density within

Expectation value for threshold shift of single defect group:

|∆Vth(t)| ∝ dτe

τe + τc︸ ︷︷ ︸

a(VGS)

+(

|∆Vth(t0)| − dτe

τe + τc︸ ︷︷ ︸

a(VGS)

)

exp(

−( 1

τe+

1

τc︸ ︷︷ ︸

b(VGS)

)

t)

Bias dependence regarded by model parameters k1 and k2:

|∆Vth(t)| =(

k1VGS

)k2

a+(

|∆Vth(t0)| −(

k1VGS

)k2

a)

exp(

−bt)

April 12th, 2013 10

Lehrstuhl für Technische Elektronik Technische Universität München

Markov Model for a single Defect Group

1 21: neutral state

2: positively charged

Defect group ( , ),

density within

Expectation value for threshold shift of single defect group:

|∆Vth(t)| ∝ dτe

τe + τc︸ ︷︷ ︸

a(VGS)

+(

|∆Vth(t0)| − dτe

τe + τc︸ ︷︷ ︸

a(VGS)

)

exp(

−( 1

τe+

1

τc︸ ︷︷ ︸

b(VGS)

)

t)

Bias dependence regarded by model parameters k1 and k2:

|∆Vth(t)| =(

k1VGS

)k2

a+(

|∆Vth(t0)| −(

k1VGS

)k2

a)

exp(

−bt)

April 12th, 2013 10

Lehrstuhl für Technische Elektronik Technische Universität München

Where do the model parameters k1 and k2 come from?

EF

Gate

EC

ChannelDielectric

VGS ≈ Vth

Channel ChannelGate GateDielectric Dielectric

VGS = Vs,1 VGS = Vs,2

EC

EC

EV

EV

EF

EF

EF

EF

EF

EV

N1N1

∆N

Number of active traps is bias dependent [2]

Make amplitude of ∆Vth bias dependent with prefactorA = (k1VGS)

k2 [1]

April 12th, 2013 11

Lehrstuhl für Technische Elektronik Technische Universität München

Content

1 Introduction and Motivation

2 Physical NBTI Model

3 New Simulation Method for NBTI in Analog CMOS Circuits

4 SC Comparator

5 SAR ADC

6 Conclusion and Outlook

7 References

April 12th, 2013 12

Lehrstuhl für Technische Elektronik Technische Universität München

Modeling Dynamic NBTI on Circuit Level

S

M1

ΔVth(t,VGS)

GextGint

Verilog-A BSim4

Dynamic ∆Vth modeled inVerilog-A subcircuit

Gext

S

Gext

Gint

Verilog-A model acts as voltagecontrolled voltage source(VCVS)

∆Vth adapted online duringtransient simulation

April 12th, 2013 13

Lehrstuhl für Technische Elektronik Technische Universität München

Example for Transient NBTI Simulation

Example circuit & VGS, ∆Vth(t) of Mp1:

Mp1

ΔVth

Vin

−1.4

−1.2

−1

−0.8

−0.6

VG

S [V

]

0 5 10 15−3

−2

−1

0

Time [µs]

∆ V

th [m

V]

April 12th, 2013 14

Lehrstuhl für Technische Elektronik Technische Universität München

LTERely Simulator

Netlist

Analyzer (1)

Virgin Netlist

Aged Netlist

Verilog-A (1)

NBTI Modelfor PMOS (1)

Automated reliabilitysimulation of complexanalog blocks

Verilog-A model forshort term reliability

Extrapolator for longterm reliability

April 12th, 2013 15

Lehrstuhl für Technische Elektronik Technische Universität München

Content

1 Introduction and Motivation

2 Physical NBTI Model

3 New Simulation Method for NBTI in Analog CMOS Circuits

4 SC Comparator

5 SAR ADC

6 Conclusion and Outlook

7 References

April 12th, 2013 16

Lehrstuhl für Technische Elektronik Technische Universität München

Switched Capacitor Comparator

Mp1

Mn1

Mp2

Mn2

C1 C2

CL

outVin

Vref

Use case:VDD = 1.3 V

Vref = 0.65 V

Clock Phase φ1 : Offset sampled on C1 and C2

Clock Phase φ2 : Comparator Mode

April 12th, 2013 17

Lehrstuhl für Technische Elektronik Technische Universität München

Switched Capacitor Comparator

Use case:VDD = 1.3 V

Vref = 0.65 V

Clock Phase φ1 : Offset sampled on C1 and C2

Clock Phase φ2 : Comparator Mode

NBTI critical for Mp1: Largest stress for Vin = 0 V

April 12th, 2013 17

Lehrstuhl für Technische Elektronik Technische Universität München

SC Comparator: Test Case

Verify correct function by input step from Vin = 0 V to Vref + 20 µV:

0

0.65

1.3

φ 1 [V]

0

0.65

1.3

φ 2 [V]

0

0.65

1.3

Vin

[V] V

in = V

ref + 20µV

0 1 2 3 4 5 6 7 8 9 100

0.65

1.3

Vou

t [V]

Time [µs]

April 12th, 2013 18

Lehrstuhl für Technische Elektronik Technische Universität München

SC Comparator: Include Dynamic NBTI

Consider only short term stress:

0

0.65

1.3

Vin

[V] V

in = V

ref + 20µV

0

0.65

1.3

Vou

t [V]

no NBTI with NBTI

0 1 2 3 4 5 6 7 8 9 10

−1

−0.5

0

Time [µs]

∆ V

th [m

V]

∆ Vth of Mp1

Failure is caused by dynamic NBTI component, before end of life time

April 12th, 2013 19

Lehrstuhl für Technische Elektronik Technische Universität München

SC Comparator: Include Dynamic NBTI

Consider only short term stress:

0

0.65

1.3

Vin

[V] V

in = V

ref + 20µV

0

0.65

1.3

Vou

t [V]

no NBTI with NBTI

0 1 2 3 4 5 6 7 8 9 10

−1

−0.5

0

Time [µs]

∆ V

th [m

V]

∆ Vth of Mp1

Failure is caused by dynamic NBTI component, before end of life time

April 12th, 2013 19

Lehrstuhl für Technische Elektronik Technische Universität München

SC Comparator: Offset Compensation Failure

Offset compensation failure due to NBTI relaxation:

0

.65

1.3

Vout[V

]

�1.3

�.65

VG

S[V

]

0 1 2 3 4 5 6 7 8 9 10�1

�.5

0

Vth

[mV

]

Time [µs]

Contribution of Mp1 to Voff,

sampled on C1

Relaxation: Voff reduces,

i.e. sampled offset no longer valid

April 12th, 2013 20

Lehrstuhl für Technische Elektronik Technische Universität München

SC Comparator: 10a Stress Case

Simulation after 10a stress using the stress extrapolator

0

0.65

1.3

Vin

[V] V

in = V

ref + 20µV

0

0.65

1.3

Vou

t [V]

virgin 10a stress: dynamic 10a stress: static

0 1 2 3 4 5 6 7 8 9 10−12.5

−12

−11.5

Time [µs]

∆ V

th [m

V]

∆ Vth of Mp1 after 10a: dynamic ∆ Vth of Mp1 after 10a: static

Failure not detected by classical simulation with constant ∆Vth

April 12th, 2013 21

Lehrstuhl für Technische Elektronik Technische Universität München

SC Comparator: 10a Stress Case

Simulation after 10a stress using the stress extrapolator

0

0.65

1.3

Vin

[V] V

in = V

ref + 20µV

0

0.65

1.3

Vou

t [V]

virgin 10a stress: dynamic 10a stress: static

0 1 2 3 4 5 6 7 8 9 10−12.5

−12

−11.5

Time [µs]

∆ V

th [m

V]

∆ Vth of Mp1 after 10a: dynamic ∆ Vth of Mp1 after 10a: static

Failure not detected by classical simulation with constant ∆Vth

April 12th, 2013 21

Lehrstuhl für Technische Elektronik Technische Universität München

Content

1 Introduction and Motivation

2 Physical NBTI Model

3 New Simulation Method for NBTI in Analog CMOS Circuits

4 SC Comparator

5 SAR ADC

6 Conclusion and Outlook

7 References

April 12th, 2013 22

Lehrstuhl für Technische Elektronik Technische Universität München

SAR ADC

Successive Approximation Register (SAR) principle:

S & H

NBTI degradation causes comparator offset Voff

Solution: Offset Compensation with typical requirement:

Vref ≈ 1 V, N = 10 Bit ⇒ VLSB = 1 V210

≈ 1 mV

i.e. residual Voff < 1 mV necessary

Unproblematic for slowly varying Voff , but:

Even small ∆Voff < 1 mV due to short term NBTI can cause malfunction

April 12th, 2013 23

Lehrstuhl für Technische Elektronik Technische Universität München

SAR ADC

Successive Approximation Register (SAR) principle:

S & H

NBTI degradation causes comparator offset Voff

Solution: Offset Compensation with typical requirement:

Vref ≈ 1 V, N = 10 Bit ⇒ VLSB = 1 V210

≈ 1 mV

i.e. residual Voff < 1 mV necessary

Unproblematic for slowly varying Voff , but:

Even small ∆Voff < 1 mV due to short term NBTI can cause malfunction

April 12th, 2013 23

Lehrstuhl für Technische Elektronik Technische Universität München

SAR ADC

Successive Approximation Register (SAR) principle:

S & H

NBTI degradation causes comparator offset Voff

Solution: Offset Compensation with typical requirement:

Vref ≈ 1 V, N = 10 Bit ⇒ VLSB = 1 V210

≈ 1 mV

i.e. residual Voff < 1 mV necessary

Unproblematic for slowly varying Voff , but:

Even small ∆Voff < 1 mV due to short term NBTI can cause malfunction

April 12th, 2013 23

Lehrstuhl für Technische Elektronik Technische Universität München

SAR ADC

Successive Approximation Register (SAR) principle:

S & H

NBTI degradation causes comparator offset Voff

Solution: Offset Compensation with typical requirement:

Vref ≈ 1 V, N = 10 Bit ⇒ VLSB = 1 V210

≈ 1 mV

i.e. residual Voff < 1 mV necessary

Unproblematic for slowly varying Voff , but:

Even small ∆Voff < 1 mV due to short term NBTI can cause malfunction

April 12th, 2013 23

Lehrstuhl für Technische Elektronik Technische Universität München

SAR ADC

Successive Approximation Register (SAR) principle:

S & H

NBTI degradation causes comparator offset Voff

Solution: Offset Compensation with typical requirement:

Vref ≈ 1 V, N = 10 Bit ⇒ VLSB = 1 V210

≈ 1 mV

i.e. residual Voff < 1 mV necessary

Unproblematic for slowly varying Voff , but:

Even small ∆Voff < 1 mV due to short term NBTI can cause malfunction

April 12th, 2013 23

Lehrstuhl für Technische Elektronik Technische Universität München

Example: 10 Bit Charge Redistribution SAR ADC

Vin

Vref

SAR ADC use case:

Fs = 1 MHz

fclk = 13 MHz

VDD = 1.3 V

Vref = VDD

Mp1

Mn1

Mp2

Mn2

CC�2 �3

CC2C

...

...

...

...CMPin CMPout ...

Comparator circuit:

Offset compensated

NBTI critical forMp1

April 12th, 2013 24

Lehrstuhl für Technische Elektronik Technische Universität München

Example: Error @ 2nd Bit

April 12th, 2013 25

Lehrstuhl für Technische Elektronik Technische Universität München

SAR ADC: Errors due to short term NBTIWrong output codes can occur for large variety of input levels

Code deviations of more than |1 LSB| were not found

Observed error rates depend on:

Input signal waveformClock frequency...

Example for full scale sine wave input @ Fs = 1 MHz:

April 12th, 2013 26

Lehrstuhl für Technische Elektronik Technische Universität München

SAR ADC: Errors due to short term NBTIWrong output codes can occur for large variety of input levelsCode deviations of more than |1 LSB| were not found

Observed error rates depend on:Input signal waveformClock frequency...

Example for full scale sine wave input @ Fs = 1 MHz:

0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.20

5

10

15

20

25

Stress Time [ms]

Err

or R

ate

[%]

fin = 100 kHzfin = 400 kHz

April 12th, 2013 26

Lehrstuhl für Technische Elektronik Technische Universität München

Guideline for Transient Error Detection

Systematic approach to detect transient BTI errors:

1. Which devices are mainly susceptible against parameter drifts?→ Confine (complex) problem

2. Study transient VGS of critical devices

3. Do large |VGS| values on critical devices occur?→ High |VGS| causes ∆Vth (NBTI stress)

4. Abrupt changes in VGS possible?→ Dynamic ∆Vth can cause a transient error

April 12th, 2013 27

Lehrstuhl für Technische Elektronik Technische Universität München

Guideline for Transient Error Detection

Systematic approach to detect transient BTI errors:

1. Which devices are mainly susceptible against parameter drifts?→ Confine (complex) problem

2. Study transient VGS of critical devices

3. Do large |VGS| values on critical devices occur?→ High |VGS| causes ∆Vth (NBTI stress)

4. Abrupt changes in VGS possible?→ Dynamic ∆Vth can cause a transient error

April 12th, 2013 27

Lehrstuhl für Technische Elektronik Technische Universität München

Guideline for Transient Error Detection

Systematic approach to detect transient BTI errors:

1. Which devices are mainly susceptible against parameter drifts?→ Confine (complex) problem

2. Study transient VGS of critical devices

3. Do large |VGS| values on critical devices occur?→ High |VGS| causes ∆Vth (NBTI stress)

4. Abrupt changes in VGS possible?→ Dynamic ∆Vth can cause a transient error

April 12th, 2013 27

Lehrstuhl für Technische Elektronik Technische Universität München

Guideline for Transient Error Detection

Systematic approach to detect transient BTI errors:

1. Which devices are mainly susceptible against parameter drifts?→ Confine (complex) problem

2. Study transient VGS of critical devices

3. Do large |VGS| values on critical devices occur?→ High |VGS| causes ∆Vth (NBTI stress)

4. Abrupt changes in VGS possible?→ Dynamic ∆Vth can cause a transient error

April 12th, 2013 27

Lehrstuhl für Technische Elektronik Technische Universität München

Guideline for Transient Error Detection

Systematic approach to detect transient BTI errors:

1. Which devices are mainly susceptible against parameter drifts?→ Confine (complex) problem

2. Study transient VGS of critical devices

3. Do large |VGS| values on critical devices occur?→ High |VGS| causes ∆Vth (NBTI stress)

4. Abrupt changes in VGS possible?→ Dynamic ∆Vth can cause a transient error

April 12th, 2013 27

Lehrstuhl für Technische Elektronik Technische Universität München

Guideline for Transient Error Detection

Systematic approach to detect transient BTI errors:

1. Which devices are mainly susceptible against parameter drifts?→ Confine (complex) problem

2. Study transient VGS of critical devices

3. Do large |VGS| values on critical devices occur?→ High |VGS| causes ∆Vth (NBTI stress)

4. Abrupt changes in VGS possible?→ Dynamic ∆Vth can cause a transient error

Note:In high-precision analog circuits even small ∆Vth (≈ 1 mV) can causetran. error

April 12th, 2013 28

Lehrstuhl für Technische Elektronik Technische Universität München

Content

1 Introduction and Motivation

2 Physical NBTI Model

3 New Simulation Method for NBTI in Analog CMOS Circuits

4 SC Comparator

5 SAR ADC

6 Conclusion and Outlook

7 References

April 12th, 2013 29

Lehrstuhl für Technische Elektronik Technische Universität München

Conclusion

Physics based model for dynamic NBTI

Verilog-A model to study NBTI impact on circuit level

LTERely: Simulation of NBTI for complex analog blocks

Transient errors due to dynamic NBTI:

Example: SC Comparator & SAR ADC65 nm design: No show stopper, but:Effects will worse with further technology scaling

April 12th, 2013 30

Lehrstuhl für Technische Elektronik Technische Universität München

Conclusion

Physics based model for dynamic NBTI

Verilog-A model to study NBTI impact on circuit level

LTERely: Simulation of NBTI for complex analog blocks

Transient errors due to dynamic NBTI:

Example: SC Comparator & SAR ADC65 nm design: No show stopper, but:Effects will worse with further technology scaling

April 12th, 2013 30

Lehrstuhl für Technische Elektronik Technische Universität München

Outlook

What happens if technology is further scaled?

NBTI effects become more relevant:

Non-constant field scaling increases local stress fieldsFast trapping/detrapping enhanced by new gate materials (cf. [1])

High-κ metal gate technologies:

Same effect also on nMOSFET (PBTI)Sources for errors increase, short term effects become worse (cf. [3])

April 12th, 2013 31

Lehrstuhl für Technische Elektronik Technische Universität München

Outlook

What happens if technology is further scaled?

NBTI effects become more relevant:

Non-constant field scaling increases local stress fieldsFast trapping/detrapping enhanced by new gate materials (cf. [1])

High-κ metal gate technologies:

Same effect also on nMOSFET (PBTI)Sources for errors increase, short term effects become worse (cf. [3])

April 12th, 2013 31

Lehrstuhl für Technische Elektronik Technische Universität München

Thank you for your attention

Please feel free to ask questions

April 12th, 2013 32

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Content

1 Introduction and Motivation

2 Physical NBTI Model

3 New Simulation Method for NBTI in Analog CMOS Circuits

4 SC Comparator

5 SAR ADC

6 Conclusion and Outlook

7 References

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References I

T. Grasser, P. Wagner, H. Reisinger, T. Aichinger, G. Pobegen,M. Nelhiebel, and B. Kaczer.Analytic modeling of the bias temperature instability usingcapture/emission time maps.In Electron Devices Meeting (IEDM), 2011 IEEE International, pages27.4.1 –27.4.4, dec. 2011.

T. Grasser, B. Kaczer, H. Reisinger, P.-J. Wagner, andM. Toledano-Luque.On the frequency dependence of the bias temperature instability.In Reliability Physics Symposium (IRPS), 2012 IEEE International,pages XT.8.1 –XT.8.7, april 2012.

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Lehrstuhl für Technische Elektronik Technische Universität München

References II

K. Zhao, J.H. Stathis, B.P. Linder, E. Cartier, and A. Kerber.PBTI under dynamic stress: From a single defect point of view.In Reliability Physics Symposium (IRPS), 2011 IEEE International,pages 4A.3.1 –4A.3.9, april 2011.

M. A. Alam.A Critical Examination of the Mechanics of Dynamic NBTI forPMOSFETs.In Proc. IEDM ’03 Technical Digest Electron Devices Meeting IEEEInt, 2003.

M.A. Alam, H. Kufluoglu, D. Varghese, and S. Mahapatra.A comprehensive model for PMOS NBTI degradation: Recentprogress.Microelectronics Reliability, 47(6):853 – 862, 2007.

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Lehrstuhl für Technische Elektronik Technische Universität München

References III

M.A. Alam and S. Mahapatra.A comprehensive model of PMOS NBTI degradation.Microelectronics Reliability, 45(1):71 – 81, 2005.

F.R. Chouard, M. Fulde, and D. Schmitt-Landsiedel.Reliability assessment of voltage controlled oscillators in 32nm high-κ metal gate technology.In ESSCIRC, 2010 Proceedings of the, pages 410 –413, sept. 2010.

S. Drapatz, K. Hofmann, G. Georgakos, and D. Schmitt-Landsiedel.Impact of fast-recovering NBTI degradation on stability oflarge-scale SRAM arrays.In Solid-State Device Research Conference (ESSDERC), 2010Proceedings of the European, pages 146 –149, sept. 2010.

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References IV

Michael Fulde.Variation Aware Analog and Mixed-Signal Circuit Design inEmerging Multi-Gate CMOS Technologies.Springer Series in Advanced Microelectronics. SpringerScience+Business Media, Dec. 2010.

M. Fulde, D. Schmitt-Landsiedel, and G. Knoblinger.Transient Variations in Emerging SOI Technologies: Modeling andImpact on Analog/Mixed-Signal Circuits.In Circuits and Systems, 2007. ISCAS 2007. IEEE InternationalSymposium on, pages 1249 –1252, may 2007.

W. Goes, F. Schanovsky, T. Grasser, H. Reisinger, and B. Kaczer.Advanced Modeling of Oxide Defects for Random Telegraph Noise.In Noise and Fluctuations (ICNF), 2011 21st InternationalConference on, pages 204 –207, june 2011.

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References V

Tibor Grasser.Stochastic charge trapping in oxides: From random telegraph noiseto bias temperature instabilities.Microelectronics Reliability, 52(1):39 – 70, 2012.

T. Grasser, T. Aichinger, G. Pobegen, H. Reisinger, P. Wagner,J. Franco, M. Nelhiebel, and B. Kaczer.The ’permanent’ component of nbti: Composition and annealing.In Reliability Physics Symposium (IRPS), 2011 IEEE International,pages 6A.2.1 –6A.2.9, april 2011.

T. Grasser, T. Aichinger, H. Reisinger, J. Franco, P.-J. Wagner,M. Nelhiebel, C. Ortolland, and B. Kaczer.On the ’permanent’ component of nbti.In Integrated Reliability Workshop Final Report (IRW), 2010 IEEEInternational, pages 2 –7, oct. 2010.

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References VI

T. Grasser and B. Kaczer.Evidence that two tightly coupled mechanisms are responsible fornegative bias temperature instability in oxynitride mosfets.Electron Devices, IEEE Transactions on, 56(5):1056 –1062, may2009.

T. Grasser, B. Kaczer, W. Goes, T. Aichinger, P. Hehenberger, andM. Nelhiebel.A two-stage model for negative bias temperature instability.In Reliability Physics Symposium, 2009 IEEE International, pages 33–44, april 2009.

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References VII

T. Grasser, B. Kaczer, W. Goes, H. Reisinger, T. Aichinger,P. Hehenberger, P. Wagner, F. Schanovsky, J. Franco, M.T. Luque,and M. Nelhiebel.The paradigm shift in understanding the bias temperature instability:From reaction-diffusion to switching oxide traps.Electron Devices, IEEE Transactions on, 58(11):3652 –3666, nov.2011.

T. Grasser, B. Kaczer, H. Reisinger, P.-J. Wagner, andM. Toledano-Luque.Recent developments in understanding the bias temperatureinstability.In Microelectronics (MIEL), 2012 28th International Conference on,pages 315 –322, may 2012.

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References VIII

T. Grasser, H. Reisinger, P. Wagner, F. Schanovsky, W. Goes, andB. Kaczer.The time dependent defect spectroscopy (tdds) for thecharacterization of the bias temperature instability.In Reliability Physics Symposium (IRPS), 2010 IEEE International,pages 16 –25, may 2010.

V. Huard, M. Denais, and C. Parthasarathy.NBTI degradation: From physical mechanisms to modelling.Microelectronics Reliability, 46(1):1 – 23, 2006.

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References IX

V. Huard, C. Parthasarathy, N. Rallet, C. Guerin, M. Mammase,D. Barge, and C. Ouvrard.New characterization and modeling approach for NBTI degradationfrom transistor to product level.In Electron Devices Meeting, 2007. IEDM 2007. IEEE International,pages 797 –800, dec. 2007.

Cadence Design Systems Inc.RELIABILITY SIMULATION IN INTEGRATED CIRCUIT DESIGN.Available onlinehttp://w2.cadence.com/whitepapers/5082 ReliabilitySim FNL WP.pdf.

Kjell O. Jeppson and Christer M. Svensson.Negative bias stress of MOS devices at high electric fields anddegradation of MNOS devices.Journal of Applied Physics, 48(5):2004–2014, 1977.

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References X

B. Kaczer, T. Grasser, P.J. Roussel, J. Franco, R. Degraeve,L. Ragnarsson, E. Simoen, G. Groeseneken, and H. Reisinger.Origin of nbti variability in deeply scaled pfets.In Reliability Physics Symposium (IRPS), 2010 IEEE International,pages 26 –32, may 2010.

B. Kaczer, S. Mahato, V.V. de Almeida Camargo,M. Toledano-Luque, P.J. Roussel, T. Grasser, F. Catthoor,P. Dobrovolny, P. Zuber, G. Wirth, and G. Groeseneken.Atomistic approach to variability of bias-temperature instability incircuit simulations.In Reliability Physics Symposium (IRPS), 2011 IEEE International,pages XT.3.1 –XT.3.5, april 2011.

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References XI

B. Kaczer, P.J. Roussel, T. Grasser, and G. Groeseneken.Statistics of multiple trapped charges in the gate oxide of deeplyscaled mosfet devices - application to nbti.Electron Device Letters, IEEE, 31(5):411 –413, may 2010.

J. Keane, Xiaofei Wang, D. Persaud, and C.H. Kim.An all-in-one silicon odometer for separately monitoring hci, bti, andtddb.Solid-State Circuits, IEEE Journal of, 45(4):817 –829, april 2010.

Tae-Hyoung Kim, R. Persaud, and C.H. Kim.Silicon odometer: An on-chip reliability monitor for measuringfrequency degradation of digital circuits.Solid-State Circuits, IEEE Journal of, 43(4):874 –880, april 2008.

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References XII

T.H. Lee and A. Hajimiri.Oscillator phase noise: a tutorial.Solid-State Circuits, IEEE Journal of, 35(3):326 –336, march 2000.

Zhihong Liu, B.W. McGaughy, and J.Z. Ma.Design tools for reliability analysis.In Design Automation Conference, 2006 43rd ACM/IEEE, pages 182–187, 0-0 2006.

Franco Maloberti.Analog Design for CMOS VLSI Systems.Kluwer Academic Publishers, 2001.

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References XIII

E. Maricau, Leqi Zhang, J. Franco, P. Roussel, G. Groeseneken, andG. Gielen.A compact nbti model for accurate analog integrated circuitreliability simulation.In Solid-State Device Research Conference (ESSDERC), 2011Proceedings of the European, pages 147 –150, sept. 2011.

J. Martin-Martinez, R. Rodriguez, M. Nafria, and X. Aymerich.Time-dependent variability related to bti effects in mosfets: Impacton cmos differential amplifiers.Device and Materials Reliability, IEEE Transactions on, 9(2):305–310, june 2009.

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References XIV

H. Miki, M. Yamaoka, N. Tega, Z. Ren, M. Kobayashi, C.P. D’Emic,Y. Zhu, D.J. Frank, M.A. Guillorn, D. Park, W. Haensch, andK. Torii.Understanding short-term bti behavior through comprehensiveobservation of gate-voltage dependence of rtn in highly scaled high-k / metal-gate pfets.In VLSI Technology (VLSIT), 2011 Symposium on, pages 148 –149,june 2011.

S. More, M. Fulde, F. Chouard, and D. Schmitt-Landsiedel.Reliability analysis of buffer stage in mixed signal application.Advances in Radio Science, 9:225–230, 2011.

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References XV

S. More, M. Fulde, F. Chouard, and D. Schmitt-Landsiedel.Reducing Impact of Degradation on Analog Circuits by ChopperStabilization and Autozeroing.In Proc. 12th Int Quality Electronic Design (ISQED) Symp, pages1–6, 2011.

L. Negre, D. Roy, F. Cacho, P. Scheer, S. Jan, S. Boret, D. Gloria,and G. Ghibaudo.Reliability characterization and modeling solution to predict aging of40-nm mosfet dc and rf performances induced by rf stresses.Solid-State Circuits, IEEE Journal of, 47(5):1075 –1083, may 2012.

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References XVI

H. Reisinger, O. Blank, W. Heinrigs, A. Muhlhoff, W. Gustin, andSchlunder C.Analysis of NBTI Degradation- and Recovery-Behavior Based onUltra Fast VT-Measurements.In Reliability Physics Symposium Proceedings, 2006. 44th Annual.,IEEE International, pages 448 –453, march 2006.

H. Reisinger, O. Blank, W. Heinrigs, A. Muhlhoff, W. Gustin, andC. Schlunder.Analysis of nbti degradation- and recovery-behavior based on ultrafast vt-measurements.In Reliability Physics Symposium Proceedings, 2006. 44th Annual.,IEEE International, pages 448 –453, march 2006.

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References XVII

H. Reisinger, T. Grasser, K. Ermisch, H. Nielen, W. Gustin, andSchlunder C.Understanding and modeling AC BTI.In Reliability Physics Symposium (IRPS), 2011 IEEE International,pages 6A.1.1 –6A.1.8, april 2011.

H. Reisinger, T. Grasser, W. Gustin, and C. Schlunder.The statistical analysis of individual defects constituting NBTI andits implications for modeling DC- and AC-stress.In Reliability Physics Symposium (IRPS), 2010 IEEE International,pages 7 –15, may 2010.

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References XVIII

M. Toledano-Luque, B. Kaczer, J. Franco, P.J. Roussel, T. Grasser,T.Y. Hoffmann, and G. Groeseneken.From mean values to distributions of BTI lifetime of deeply scaledFETs through atomistic understanding of the degradation.In VLSI Technology (VLSIT), 2011 Symposium on, pages 152 –153,june 2011.

Christoph Werner, Florian R. Chouard, Stefan Drapatz, and DorisSchmitt-Landsiedel.A statistical MOSFET Aging Model for Monte Carlo Simulationswith HSpice.In Synopsys User Group (SNUG), 2012 Germany, 2012.

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References XIX

G.I. Wirth, R. da Silva, and B. Kaczer.Statistical Model for MOSFET Bias Temperature InstabilityComponent Due to Charge Trapping.Electron Devices, IEEE Transactions on, 58(8):2743 –2751, aug.2011.

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