Presented at Nuclear Data Symposium 2006,
Tokai, Japan, January 26, 2007

Nuclear data relevant to single event upsetsin semiconductor memories inducedby cosmic-ray neutrons and protons- Role of nuclear data in our IT society Cosmic-rays
Device layer

Memory devices

SiliconChip

Elementaryparticle

Silicon Nucleus

Yukinobu Watanabe
Department of Advanced Energy Engineering Science,Kyushu University

Table of Contents
1. Introduction
2. Model for SEU simulation and nuclear data
3. Results and discussion
4. Summary and future plans

In cooperation withAkihiro Kodama and Kouta NishijimaIntroduction
Single-Event Upset (SEU)- One of the radiation effects caused in microelectronic
devices (e.g., semiconductor memory devices) used in various
radiation environments- When a memory device is exposed to radiations, the memory
state of a cell can be flipped from a 1 to a 0 or vice versa,
resulting in malfunction caused by an error in a bit.
- “Transient" effects caused by a single ionizing particle

Soft Error or Soft Failure
The SEUs (Soft errors) in devices and circuits have recently
been recognized as a key reliability concern for many current
and future silicon-based integrated circuit technologies.

November 13, 2000

Note that the cosmic-ray
induced SEU was predictedby Ziegler@IBM andLandford@Yale Univ. (1979).

Sun Screen
THE MYSTERIOUS GLITCH has been popping up since late last year. At a
new Web company in San Francisco, a telecommunications company in theMidwest, a Baby Bell in Atlanta, an Internet domain registry on the East Coast-for no apparent reason, high-end servers made by Sun Microsystems

suddenly crashed.
・・・・・・
Sun says it has finally figured out what's wrong. It is an odd problem
involving stray cosmic rays and memory chips in the flagship Enterpriseserver line, whose models are priced at $50,000 to more than $1 million. Yet
Sun won't fix all of the servers it has sold; instead it will make repairs when it
deems them necessary.
http://www.forbes.com/forbes/2000/1113/6613068a_print.html

Rough estimation of SER in our daily life
1000 FIT = mean time to failure : 114 year (=106 hr) / device
Cell phone
4Mbit memory with 1000FIT/1Mbit on board
1 error / 28 year
Network equipment having SRAM with 600FIT/1Mbit on board
High-end router : 10Gbit SRAM

1 error / 170 hours

100Gbit SRAM
Laptop PC in airplane

1 error / 17 hours

600FIT/1Mbit Æ 100,000 FIT/1Mbit@10,000 m in altitude
256MB (2Gbit) memories on board
1 error / 5 hours
Source : http:/www.ednjapan.com/content/issue/2005/02/feature/feature02.html

Soft error rate in DRAM and SRAM
DRAM

SRAM

引用）
日経エレクトロニクス2005.7.4

Physics related for SEU phenomena
Multi-physics & Multi-scale simulation
Nuclear physics
Femto-scale

Cosmic-ray physics

Nano tomicro-scale
Atomic and radiation physics

Device physics and engineeringCosmic-ray environment on the earth-310-410-5

Neutrons-610-710-810-910-410-5

Latitude: 42.35deg. N
Longitude: 288.95 deg.
Altitude: 0 ft.
2Press. = 1033 g/cm

10-6IBM model

10-7

10-8

10-92

Muons
10-3

Neutrons

Latitude: 42.35deg. N
Longitude: 288.95 deg.
Altitude: 0 ft.
2Press. = 1033 g/cm
GMR= 1.7 GV

Flux (n/cm MeV sec)

102Flux (n/cm MeV sec)

1010-22

ProtonsTotal flux/cm -yr :Muons = 65466
Neutrons = 44812
Pions = 48.4
Protons = 360

110Pions

100
1000
Particle energy (MeV)

Sea level @ New York

4102

10Total flux/cm -yr :Neutrons = 178210

1001000
Particle energy (MeV)

Neutron flux ＠Tokyo

about 12 n/cm2 hfor above 10 MeV
Ref.) J.F. Ziegler, “Terrestrial cosmic rays”, IBM J. Res. Develop. Vol. 40, No. 1 (1996), p. 19

104

Radiation flux in Space

補足放射線帯陽子

銀河宇宙線
太陽高エネルギー陽子

Ref.) K. Oishi, “Issues in space radiation shielding for linar base”, JAERI-Conf95-016 (1995), p.125Nuclear processes relevant to SEUs
- Production of secondary charged particles and fragments
via nuclear reactions with a silicon nucleus- Data of their energy and angular distributions are necessary.

(n, p)
Elastic
scattering

Transmutation
28Si(n, α)

Inelastic
scattering
Captureγ-ray

Fragmentation

Charge collection in a silicon junction
drift

diffusion

Qcollection = ∫t max

0i (t )dt

Ref.) Radiation effects and soft errors
in integrated circuits and electronic
devices, p.17

Flow chart of SEU simulation
Devicestructure

Cosmic-raySpectrum

Nuclearreactiondatabase

ChargeChargedeposition
deposition
calculation
calculation

Atomic database（stopping powerand range）

SRIM code, etc.
Nuclear model
calculation andexperimental data

ChargeChargetransporttransport Using device simulator
andandcollection
collection
Qcollection ≥ Qc
Upset
Upsetcross
crosssection
sectionSoft-error
Soft-errorrate
rate

Qc: Critical charge

Semi-empirical modelThis model calculates nucleon-induced SEU cross section using
experimental heavy-ion induced SEU data.
Barak et al., IEEE NS Vol. 43, No. 3, pp. 979-984 (1996).
Barak, IEEE NS Vol. 47, No. 3, pp. 545-550 (2000).

σ SEU ( Ein ) = N Si ⋅ σ N ( Ein ) ∫ g ( Ein , Ed , d )σ HI ( Ed )d Ed= N Si ⋅ σ N ( Ein ) ⋅ Vint ⋅ ∫ g ( Ein , Ed , d )h( Ed )d Ed
The number of nuclear
Distribution function of Dependence of charge
reactions in ROI per unit flux the energy deposited in collection efficiency ondeposited energy
σ N ( Ein ) = σ el . ( Ein ) + σ react . ( Ein ) the sensitive volume(d: sensitive depth)
Normalized
Heavy-ion SEU datas⎫⎪⎧EE−⎡⎤⎪∞
0dh( Ed ) = σ HI ( Ed ) / σ HI = 1 − exp⎨− ⎢⎥ ⎬W⎪⎩ ⎣⎦ ⎪⎭E d = d ⋅ LET
Weibull function

HI-induced SEU cross sections⎛⎧⎪ ⎡ L − L0 ⎤ ⎫⎪ ⎞⎟∞ ⎜σ HI ( L) = σ HI 1 − exp⎨− ⎢⎬⎟⎥⎜⎪⎩ ⎣ W ⎦ ⎪⎭ ⎠⎝1010-610-710-8HI

2

σ [cm /bit]

SRAM 256K(HI_62256)-5

Exp.
Weibull Fitting

010203040
2

LET[MeVcm /mg]

5060

Monte Carlo calculation
σ SEU ( Ein ) = ∫ σ ED ( Ein , Ed , SV ) ⋅ h( Ed )d Edσ ED ( Ein , Ed , SV ) ≡ N Si ⋅Vint ⋅ σ reac ( Ein ) ⋅ g ( Ein , Ed , d )Rectangular parallelepiped geometry
Lg1
Lg2

Ls1

Sensitive
volume (SV) • Nuclear reaction event generation

Ls2

d+ + + + + +- - ++• Random sampling of a reaction point

28Si

Lg3

（secondary ion, energy and angle）
using nuclear reaction databasecreated by QMD/GEM calculation
and JENDL/HE-2004 for elastic
scattering (exclusive, inclusive)
Up to 1 GeV• Energy deposition due tosecondary ion using dE/dx andrange calculated by SRIM code

Nuclear reaction database41027p+ Al@180MeV

3Cross section (mb)

10experimental
QMD/GEM

210110010-1

10-210051015202530

Mass number
101100p+27Al@180MeV
20 degd2σ/dEdΩ(mb/sr MeV)

Neutron elastic scattering(JENDL/HE-2004)

10-1

10-2

10-3

10-4

10-510-6

A= 2240 deg(x 0.1)70 deg(x0.01)

Ref.: K. Kwiatkowski et al.
05101520E(MeV)2530

PRL 50, 1648 (1983)

Incident energy dependence ofenergy deposition spectra• Proton incidence∞3• Sensitive Volume : V = σ HI ⋅ d = 5.57 × 5.57 × 2µm

10-1110-1210-1310-1410-15

20MeV
50MeV
100MeV
300MeVED2σ [cm /MeV]DRAM 4Mb (MT4C4001)

0.0

2.0

4.0

6.0

8.0

Deposited Energy[MeV]

10.0

Experimental SEU cross sections
SRAM

DRAM

Neutron
Neutronirradiation
irradiation

ProtonProtonirradiation
irradiationRef.) K. Johansson et al., IEEE Trans. Nucl.
Sci. 45, 2519 (1998).

引用） 伊部ら、応用物理Vol.70, No.11 (2001)

Comparison with experimental data (I)Sensitive area =32K x 8 bit SRAM (HM62256)∞σ HI= 76.2 µm 2d = 2.2 or 0.9 µm

10-1210-1310-1410-15HM62256
p-SEU cross section

σSEU2[cm /bit]

HI-SEU cross sectionExp.
d=0.9µmd=2.2µm
0100

200

300

400

Proton Energy[MeV]Ref.) P.D. Bradley and E. Normand, IEEE NS Vol. 45, No.6 pp. 2929-2940 (1998)

500

Comparison with experimental data (II)Sensitive depth = 2 µm
SRAM 16Kb (HM6516)

σSEU[cm2/bit]

σSEU[cm2/bit]

DRAM 4Mb (MT4C4001)-1210-1310-1310-1410-1410Exp.
present work

-1510Exp.
present work

-1510-1650100150200-1950100150200-1210-13DRAM 4Mb (KM41C4000-Z)

10Exp.
present work

-14-15100

50100150

Proton Energy[MeV]200

10-1510-1650100150200

DRAM 16 Mb (IBM_16MEG)-1410210

σSEU[cm2/bit][cm /bit]
SEU-1310-140

Proton Energy[MeV]

σσSEU[cm2/bit]-121010Exp.
present work

Proton Energy[MeV]SRAM 256Kb (62256R)-11-1710100

Proton Energy[MeV]

10-1610-18100-151010-1610DRAM 4Mb (IBM01G9274)-1410

σSEU[cm2/bit]-1210Exp.
present work

-1510-1610-1710Exp.
present work

-1810-1910050100150

Proton Energy[MeV]200050100150200

Proton Energy[MeV]Exp. ref.) P. Calvel et al., IEEE NS 43, No.6 (1996) 2827.

Discussion(a) Difference in n-SEU and p-SEU(b) Effect of elastic scattering on SEU(c) Incident energy dependence of secondary
ions having significant contribution to SEU(d) Effect of simultaneous multiple ions emission- Inclusive (conventional) nuclear datavs Exclusive (event-by-event) -(a) n-SEU and p-SEU
4Mb SRAM, 0.5 µm(HM628512ALP-7)

Sensitive depth = 2 µm
SRAM 4Mb
HM628512A-13

σSEU[cm2/bit]

10-14

10p-SEU (exp.)
p-SEU (cal.)n-SEU (cal.)-15

10-1610Ref.) C.S. Dyer et al., IEEE NS Vol.51, No.5, 2817 (2004)

0100

200300400
Incident energy[MeV]500

(b) Effect of elastic scattering
410

Sensitive volume: 1 x 1 x 1 µm3

281.0310Ec210Neutron Energy[MeV]1004.0Mg24
Al27elast3.00.11MeV(5fC)
022MeV(10fC)
0.45MeV(20fC)
1.1MeV(50fC)

0.8

totalelasticreaction
10Mean Emission Energy[MeV]h ( E d ) = Θ( E d − E c )ratio(σelast/σtotal)

Cross Section[mb]n+ Si
JENDL/HE-2004

0.6

0.4

< 20%
0.2

2.0

0.0
020406080

100

Neutron Energy[MeV]

1.0Threshold energy region for SEU < 20 MeV
020406080

100

Neutron Energy[MeV]

120140(c) Incident energy dependence of secondary ionshaving significant contribution to SEU
Cubic geometry: Lg=10 µm (interaction region)
Ls = 1µm (sensitive region)h ( E d ) = Θ ( E d − Ec )p-SEU

Secondary Ion(1) Qc= 50 fC (1.1 MeV)
PSiAlMg
NaNe
FO
NC
B
BeLi
He
H

(2) Qc= 10 fC (0.22 MeV)P
SiAlMg
Na
Ne
F
O
N
C
B
BeLi
He
H

100MeV
200MeV
300MeV
400MeV
1GeV

051015fraction[%]202530100MeV
200MeV
300MeV
400MeV
1GeV

051015fraction[%]202530(d) Effect of simultaneous multiple ions emission
JQMD/GEM calculation for n + 28Si reactionDependence of
atomic number

Mean number of
secondary ions
8320MeV
65MeV150MeV
500MeV6214Energy
[MeV]

500

2150
650

Mean Emission Ion Number

4200200

400

600

800

1000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

Atomic Number

Neutron Energy[MeV]

Low LET ions

Neut
ron

Mean Emission Number

10High LET ions ( ~ 1)

Inclusive data vs Exclusive data
SEU cross sections as a function of critical energy Ech ( E d ) = Θ( E d − E c )∞σ SEU ( En , Ec ) = ∫ σ ED ( En , Ed , SV ) ⋅ h( Ed )d Ed = ∫ σ ED ( En , Ed , SV )dEd
EcEn = 150 MeV(1) SV= 1.0×1.0×1.0 µm3-9(2) SV=20.0×20.0×1.0 µm3

σSEU(Ec) [cm2/bit]

1010-1310-10-1410-1110-1210-1310-1410

Cal.1 Inclusive DDX data
Cal.2 Multiple ions emission

10-15
10-16

10-170.0

2.0

4.0
6.0
Critical Energy [MeV]

8.0

10.0

0.0

2.0

4.0
6.0
Critical Energy[MeV]

8.0

Qc [fC] = 44.4 * Ec [MeV]

10.0

Energy deposition spectrum of Si detector(Inclusive DDX data .vs. Multiple ions emission)
Surface barrier
detector

300 MeV
protonsp+Sip+Si

S=10mm ,d=2µm,E =300MeV

S=10mm2,d=100µm,E =300MeV

2in

410210010-210-4

Integrated Events[1/10 /cm ]051015

Energy Deposition[MeV]2Exp.('96)
Exp.('00)
Cal.1 inclusive DDX data
Cal.2 multiple ions emission

105Exp.('96)
Cal.1 Inclusive DDX data
Cal.2 multiple ions emission

71072

Integrated Events[1/10 /cm ]in2010310110-110-3010203040506070

Energy Deposition[MeV]

Exp.data : J. Barak et al., IEEE Trans. on Nucl. Sci. 43, No.3 (1996) p.979; ibid., 47. No.3 (2000), p.545.

80

Summary
Overview of nucleon-induced single-event upset
phenomena
Calculation of SEU cross sections using the semiempirical model based on the sensitive volumeconcept
Influences of the nuclear data on SEU simulation:(a) n-SEU vs p-SEU(b) elastic scattering(c) secondary reaction products(d) multiple ions emission : inclusive vs exclusiveFuture : Nuclear data
More measurements of DDXs of secondary ions over thewide mass range are required for testing the predictions ofreaction models and their refinement.
H. Machner et al., PRC 73, 044606 (2006): He, Li, Be, B from 200 MeV p+Al
10-210-310-410-510-620 degree

DDX[mb/MeV sr]

DDX [mb/MeV sr]

27Al(p,6Li)

fitting
QMD/GEMExp.
0204060
ε[MeV]

80

100120

Proposal of a new experiment using the inverse kinematics@RIBF, RIKEN Æ 28Si(1H,X)

Critical charge for SRAM
310121010011010-1

Critical Charge[fC]

Critical Energy[MeV]

10010600nm 350nm 250nm 180nm 130nm 100nm 70nm 50nm
1994 1997 1999 2002 2005 2008 2011
1992

Technology Generation
P. Shivakumar et al., Int. Conf. on Dependable Systems and Networks, IEEE Proc. (2002).

Improvement of QMD calculation
protondeuterontriton110

D=2.3 fm, R0=3.5 fm,
h0=260 MeV/c fm

1-1

dσ/dE (mb/MeV)

10exp
original
new-2

10-3

1020
34He

110He6080

100E (MeV)

n+28Si@96MeV

1-1

10-2

10-3

1040020406080

0E (MeV)

20406080

GEM code for statistical
decay calculation after QMD
cal. up to Tsw=100 fm/c
Measurement:
100 U. Tippawan et al.,
PRC69, 064609 (2004).

Future : energy-deposition process
Spatial distribution of initially-deposited charges

track structure effect
Energy straggling

100MeV proton
1µm Si cube

δ-ray

R.A. Weller etal., IEEE Nucl.
Sci. 50 (2003).