Physics-Based Simulation of Radiation Effects in IC

Mask Layout

3D TCAD Model

Particle Sample

Process Rule

Particle Simulation

...

Gds2mesh

Gseat/VisualParticle

TCAD Simulation

Statistical Analysis

Flipped Not flipping

RunSEU

Particle Simulation

Particle Simulation

TCAD Simulation

TCAD Simulation

...

Genius/VisualTCAD

Unique Technologies● Fully-physical simulation framework for radiation effects● TCAD simulator able to handle over 1 million mesh nodes● From space radiation environment to SEU rate, end-to-end solution● Estimating small probability with statistical analysis

Physics-Based Simulation of Radiation Effects in IC

Framework and Modules

● 3D modeling Gds2mesh● Particle simulation Gseat/VisualParticle● TCAD simulation Genius/VisualTCAD● Integrative framework RunSEU

Integrated Solutions for EDA / TCAD / RadHard

SolutionsCogenda

Fully-Physical Other

TCAD-basedOther

Spice-based

Number of TCAD simulated transistors 1 – 30 1 – 6

Number of grid nodes in TCAD model < 500 万 < 50 万 –

Number of spice-simulated transistors > 1,000 > 1,000 >1,000,000

Parasitic BJT transistor effects

Mask layout and isolation effects

Particle transport physics

Randomness of particle transport

Radiation source Ion/Proton/Neutron/Electron/Photon Ion –

Time to analyze the SEU of a single SRAM cell (8-core parallel computation) ~ 30 mins ~ 30 mins < 1 min

Suitable application SEE, Dose rate, TID SEE, Dose rate TID

Number of events analyzed > 10,000 (w/ statistical enhance)

< 100 > 10,000

Cogenda data points:Transient of two switches (rise/fall), 2 CPUs (Xeon 5620)

Other TCAD data points:1: 6T SRAM, 45K mesh nodes, transient 4 CPUs yr2008 (old)2: power device , 500K mesh nodes, steady-state ? CPUs3: 6T SRAM, 1million mesh nodes, steady-state 4 CPUs yr2011 (latest)

10 100 10000.1

1

10

100

1000

10000

100000

nMO

S SR

AM

Inve

rter

NA

ND

2 MU

X2

Latc

h D-F

F

Traditional

Power (Traditional)

Fast

Power (Fast)

Other TCAD tools

number of mesh nodes (x1000)

sim

ula

tion

tim

e (

min

.) ①

③②

Trad.: Fully-implicit methodFast: Half-implicit method

Presented at 2012 SISPAD

Comparison of Commercial SEU Solutions

Unique Fast-TCAD Solver, Fastest in Industry

1 active cell, 2 dummy cell, well contacts将在 NSREC 2012 发表

Fully-Physical Simulation – Every Details Matter

● Realistic 3D Models● Substrate● Metal interconnects

● Geant4-based particle simulation● Fully-integrated with Gds2mesh /

TCAD modules● Complete physics list● Suitable for all radiation sources

● Heavy-ion (left)● Proton/Neutron (right)● Electron● Photon (X-ray 、 γ-ray)

● Biased cross-section for rare reactions

Comparison with Experimental results

0 5 10 15 20 25 30 35 400.01

0.1

1

10

Experiment

Simulation

LET (MeV/cm2/mg)

σ/b

it (c

m2)

HM62V8100 SRAM SEU cross-section

H.X. Guo et al, Atomic energy science and technology, v44, pp. 1498-1504, 2010.

Ion Energy (MeV)

LET (MeV/cm2/mg)

12C6+ 80 1.73

19F8+ 104 4.33

28Si10+ 126 9.6

35Cl11+ 138 13.6

63Cu13+ 161 33.4

Simulated SEU cross-sections agree with accelerator experimental results

苏州珂晶达电子有限公司中国江苏省苏州市星湖街 328 号国际科技园五期 22 栋 306 室邮编： 215123电话： 512-67900636电邮： [email protected]网址： http://cn.cogenda.com

Cogenda Pte Ltd100 Tras Street #16-01 Amara Corporate TowerSingapore 079027Email: [email protected]: http://www.cogenda.com

System Requirement

- Redhat Enterprise Linux RHEL 5.x/6.x, 64-bit- Ubuntu Linux 12.04 LTS, 64-bit- Microsoft Windows XP/7/2008, 64bit

- Intel x86_64 or compatible- 32 GB RAM- 1 TB Harddisk

FlippedNot flipped, color indicates “affinity” to flip

● SRAM SEU problems● Most particles can not possibly

cause SRAM to flip, no need for TCAD simulation.

● Statistical importance sampling, fewer number of expensive simulations.

● Autonomous algorithms to find● Sensitive volumes● Critical charge

● Example (left)● 180nm SRAM cell● Subset 0: uniform sampling● Subset 1: importance sampling● Less variance

Statistical Sampling – the Time Saver

Presented at RADECS 2012

Subset 0:

Subset 1: