HCI / NBTI - Celestry Design Technologies, Inc.

RelXpert
The Solution for Circuit-Level,
Hot-Carrier / NBTI Simulation
RelXpert TM allows designers
and technology developers to
optimize their designs for the
best possible performance &
yield without sacrificing reliability.
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HCI / NBTI
Plot Data nmos.pre
nmos.pos
Transient Response
Fresh
Degraded
0.0 0.0 1.0 2.0 3.0 4.0 5.0
Vd (V)
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0.0 5.0n
time ( s )
10n
Fresh
Optimize Yield
Aged

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What is Hot-Carrier Injection (HCI) Induced
Degradation and Why Does it Slow Your Design Down?
With designs moving into deep submicron (DSM) levels, shorter channel lengths cause the
electric field in the channel to become larger. This causes more electrons to become
energetic or "hot". Some of these hot electrons will damage the channel-oxide interface
and lead to circuit performance degradation.
Using the device centric LDD structure
to alleviate hot-carrier injection (HCI)
damage will lower the device current
driving capability, and consequently
circuit performance. Trade-offs
between HCI design rules and
performance become increasingly
complex as technology moves
further into DSM levels. These
overly conservative HCI design
rules are a roadblock in the push
for high-performance design that
must be removed.
What is Negative Bias Temperature Instability (NBTI)
Degradation and Why Does it Cause Immediate Failure?
A high vertical electrical field at a high
temperature for tox < 50 Augstroms
causes negative bias temperature
instability (NBTI). This makes the circuit
fail immediately-you do not have to wait
ten years for lower product yield
significantly at burn-in. The major
damaging mechanism is the hole trapping
and interface state generation. Positive
bias temperature instability (PBTI) is less
significant. NBTI has become a major
concern for reliable integrated CMOS
devices because of the threshold voltage
(Vth) shift of p-MOSFET, Idsat reduction,
and 1/f noise for the DSM CMOS
semiconductor industry.
"With Celestry's products we can design more aggressively in our 0.13um CMOS
and BICMOS processes, and obtain higher performance and better density
products for our Computer Peripherals and Consumer markets, while at the
same time not compromising yield and long-term reliability."
-- STMicroelectronics

Celestry's Reliability Solutions
RelPro+ TM and BSIMPro+ TM allow the designer to generate HCI and NBTI AgeMOS TM SPICE
models for circuit simulation that factors in reliability. RelXpert TM allows designers and
technology developers to reduce performance stealing design margins by accurately simulating
HCI and NBTI degradation under realistic circuit operating conditions. RelXpert is the rule
generator and design checker you have been waiting for! The result is an optimized design that
delivers:
◆ best possible performance
◆ improved yield
◆ reliable operation
Additionally, for today's largest designs, UltraSim TM , a high-performance hierarchical circuit
simulator, provides full-chip transistor-level reliability simulations UltraSim gives the designer
real-time simulation capability:
◆ Built-in support for HCI and NBTI simulations
◆ Full-chip view of HCI effects on timing
HCI / NBTI Simulation is the
Path to Higher Performance
Without accurate HCI and NBTI simulations, you can only approximate the circuit
degradation, and will result either in excessive design margins, or design failure.
Correct HCI and NBTI simulation allows you to accurately predict a circuit's
degradation over time, enabling you to create a faster design without sacrifice of
reliability. Furthermore, guard banding (or product binning) during product test will also
be more accurate.
◆ The result is a faster chip with better HCI and NBTI reliability.
Calculate the Degradation of Each Transistor
Simply provide the SPICE netlist, Isub and Igate parameters, and one of the following
reliability model options:
◆ Degraded SPICE model parameters*
◆ AgeMOS model parameters**
RelXpert and UltraSim will use the results of SPICE simulations in its calculation of the
individual device degradation, and optionally overall circuit degradation, for a user-specified
number of years. It's like getting a sneak preview at your circuit's future performance.
*Can be obtained from BSIMProTM or BSIMPro+.
** Can be obtained from BSIMPro+
Contact Celestry Design Technologies, Inc. for details.
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Three Easy Steps to Faster Designs
Step 1: Degradation Calculation
How it works:
1. Calculate actual current waveforms from real circuit operating conditions.
2. Use these waveforms to calculate the "age" for each transistor. Lifetimes and percent
degradation can then be made (see figure below).
"We selected Celestry because of their
experience in reliability analysis and
unique 'hands-on' knowledge of deep
submicron silicon issues. Celestry's
products will aide TI in more aggressive
design shrinks and in reducing wasted
performance and silicon lost by overly
pessimistic design guardbands,"
-- TI
Lifetime (Years)
1000
100
10
Crosstalk Coupling on HC Degradation
1
0 0.1 0.2 0.3 0.4
Ccoup/Ctotal
◆ Lifetime drops 3 orders of magnitude as
coupling increased from 0 to 35%
◆ Most difficult/dangerous AC HCI phenomenon
"For our high performance designs,
HCI is an important issue. Celestry's
products make it easy for our designers
to assess and prevent circuit-level
reliability issues caused by HCI effects.
-- STMicroelectronics
NBTI Vg Dependency for Long Channel Device
log DeltaVt/Vt (%)
Delta Vt/Vt vs Time
(W/L=10u/10u, T=125C, Vd=0)
100.00%
10.00%
1.00% 1.00 10.00 100.00 1000.00
log Time (min)
Vg=1.45
Vg=1.65
Vg=1.85
The engineering efforts of Celestry and
TSMC have enhanced Celestry's hot-carrier
analysis software,"... "Offering designers a
powerful tool for digital, mixed-signal and
analog designs, particularly those using
overdrive voltages. It also gives designers a
higher level of assurance in the performance
and reliability of their designs."
-- TSMC
HC Effects & NBTI in Circuit Operation
Vit(t)
Vout(t)

Step 2: Reliability Model Options
Option 1: Aged Model
The Aged model is simply an extension
of the traditional SPICE model for HCI.
Here is how it works: After calculating
the "age" of each individual device in
your circuit, Aged model parameters
are automatically generated for the
degraded devices.
RelXpert also has options to limit the number of SPICE models generated to optimize
simulation time with accuracy.
Option 2: AgeMOS Model
The AgeMOS model from Celestry is a new
reliability analysis method for HCI and NBTI
circuit reliability simulation. AgeMOS is
transparent to any MOS SPICE model and
compatible with any simulator platform. The
AgeMOS model is a significant improvement
over other reliability models in the areas of
model generation and accurate, efficient, and
consistent circuit simulation. (Addtional
AgeMOS model information, see section on
"More on Built-in Reliability with the AgeMOS
Model"
Here is how it works: RelPro+ will allow you to take stress data, BSIMPro+ extracts the fresh
and AgeMOS models for HCI and NBTI. RelXpert, the circuit level simulator, will allow you to
analyze the circuit and view the results.
More on Built-in Reliability with the AgeMOS Model
Celestry's AgeMOS model is a methodology for deep submicron CMOS reliability modeling
and circuit simulation analysis. Using this methodology, IC manufacturers can provide a
universal model to all of their IC design customers without SPICE model or simulator platform
compatibility issues. The AgeMOS model for HCI and NBTI enables designers to do accurate
and efficient reliability simulation analysis. This ensures optimal trade-off between yield and
performance before product tape out. HCI and NBTI reliability analysis with the AgeMOS
model prevents unnecessary reliability issues. Designers can create designs and design
shrinks that are more aggressive without overly pessimistic design guard bands and
unnecessary silicon loss.
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Step 3: Reliability Simulation
Clear Results!
RelXpert lists all measured
transistors, their age degradation,
maximum Igate and Isub, and many
other device characteristics. You
can use device degradation results
to track which devices are more
prone to HCI and NBTI degradation,
and even quantify their individual
immunity to HCI and NBTI effects.
The resulting list of transistors will
give you an accurate picture of
transistor degradation, immediately
enabling you to detect and identify
the weakest spots.
Gate Level HC and NBTI Reliability Simulation
Fresh waveform vs. aged waveform with fresh
SDF and aged SDF back annotation
Here is how it works: RelPro+ will allow you to take stress data, using BSIMPro+ to get fresh
and AgeMOS models for HCI and NBTI. RelXpert, the circuit level simulator, will allow you to
analyze the circuit and view the results.
Fres
Aged
HCI and NBTI continue to be important reliability issues that
need to be properly addressed. The RelXpert tool makes it easy
for designers to assess and prevent circuit level issues caused
by these effects.
The Ultimate Design at Your Fingertips!
"Before and after degradation" waveforms give you accurate images of the circuit
degradation. This will allow you to reevaluate the status of the design and give you the
opportunity to redesign for faster, more reliable performance.

Customize the Simulation Set Up
The Simulation Set Up Window gives you the opportunity to input values specific to your design.
Specifying the Age Time allows you to accurately see the degradation of the chosen circuit at
the selected circuit age.
Lifetime Calculation lets you find out how long it will take your circuit to degrade to a certain
degradation percentage. Just input the value and RelXpert will tell you the lifetime.
The option to customize the simulation ensures that the result is accurate for the specified
characteristics of your design.
RelLink TM Interface to Cadence Analog Design Environment
RelLink (for Cadence environments) displays
individual device degradation results and backannotates
the information directly onto your
schematic.You can set RelXpert and RelLink to
flag transistors that exceed a certain degradation
threshold. Once detected, redesign the device or
circuit and simulate again!
To make the simulation process even easier and
faster, use RelXpert API. RelXpert API is a set of
library functions and utilities that allow you to call
RelXpert simulations within the familiar GUI
interface of your existing tools. Only RelXpert can
deliver this complete solution to help you push the
performance envelope without sacrificing reliability!
HCI Effect on Circuit Waveforms
Simulating circuit waveform degradation due to HCI is the key to more competitive designs.
For example, you can display the effect that HCI degradation will have on your circuit delay
and frequency waveforms.
Overshoot and Undershoot Effects Revealed!
Overshoot and undershoot can be the result of interconnect coupling or device capacitance
feedback. RelXpert can capture such phenomena. This gives you the opportunity to redesign
and ensure overshoot and undershoot are no longer threats to the performance or reliability
of your design.
Reliability Modeling Service from Celestry Labs
Celestry Labs provides HCI and NBTI reliability model generation services. Celestry has many
years of experience in reliability modeling, analysis, modeling service, and knowledge of deep
submicron process reliability issues. Provide Celestry Labs with a fresh model and they will
provide you with a reliability model in a timely fashion or Celestry Labs can provide fresh and
aged models. Additionally; services may include consulting, HCI/NBTI process assessments,
process variation monitoring, as well as training and technology transfer licensing.
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Celestry Design Technologies, Inc.
Celestry is the leading provider of physical design and analysis products
that enable integrated circuit designers to achieve optimal performance from
semiconductor process technologies. The Company offers software and
services to electronic and semiconductor companies involved with the design
of chips that are used in networking, communication, multimedia and
computing products.
Worldwide Headquarters
Celestry Design Technologies, Inc.
2560 Junction Avenue,
San Jose, CA 95134-1902, U.S.A.
Phone: (408) 451-1210
Fax: (408) 451-1211
Email: info@celestry.com
http://www.celestry.com