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Above a LET of 10 MeV/(mg/cm 2 ), space heavy ions
have low or medium energy, and their range is limited. For
example, for the Fe ion, above a LET of 28
MeV/(mg/cm 2 ), the energy is less than 1.6 MeV/u and the
range in silicon is less than 18 μm. As can be seen in
Figure 3, Fe dominates the GCR spectrum for LETs
between 10 and 28 MeV/(mg/cm 2 ). This implies that most
particles with LETs in this range that reach the sensitive
structure have a limited penetration range, which turns out
to be between 18 and 400 μm as shown in Fig. 5. This is
consistent with the penetration range of particles used for
ground testing for this LET range.
The most significant part of the LET spectra for
advanced microcircuits is the range between 0.1 to 10
MeV/(mg/ cm 2 ). Most sensitive devices have a threshold
LET less than 1 MeV/(mg/cm 2 ) and their cross section
reaches the saturation before 10 MeV/(mg/cm 2 ). It has
been shown that the threshold LET of microcircuits with
sensitive volume dimensions less than micrometers has not
changed significantly with the device scaling [2].
Therefore, except for optoelectronic devices, we do not
expect in the near future threshold LET lower than 0.1
MeV/(mg/cm 2 ), which implies that SEE can be produced
by direct ionization due to protons.
Considering the incident particle energies, the most
significant energy range is the medium energy range from
tens of MeV/u to 200 MeV/u.
Maximum energy (MeV/u)
1000
100
10
1
0.1
TAMU
Fe
GANIL
200 MeV/u
25 MeV/u
0 10 20 30 40 50 60 70 80 90
Particle atomic number
Figure 8: available beams in facilities used for SEE testing.
IPN
LBL
The Fig. 8 shows the maximum beam energies available
in facilities used for SEE testing. We can see that the most
currently used facilities (BNL, UCL, IPN) with a maximum
beam energy lower than 10 MeV/u do not cover this energy
range at all. LBL and TEXAS A&M facilities cover a part
of this range. GANIL and MSU facilities give the best
coverage of the medium energy range, but it is generally
difficult and expensive to get some beam for SEE testing in
these facilities.
UCL
BNL
MSU
IV. CONCLUSION
We have reviewed how the SEE test environment relates
to the real space environment. Low energy beams are not
representative of the most significant part of the space
environment for modern microcircuits. Medium energy
beams are a better representation of the space SEE
environment, and they also give longer ranges to allow
access to the sensitive volumes of modern devices. For
these reasons medium energy beams are more and more
necessary for SEE testing. These beams are not well
covered in the existing facilities currently used for SEE
testing.
V. REFERENCES
[1] R. Koga, “Single Event Effect Ground test issues,” IEEE TNS, vol.
43, n°2, 661-670, April 1996.
[2] A. H. Johnston, “Radiation Effects in Advanced Microelectronics
Technologies,” RADECS 1997 Proceedings, pp. 1-16.
[3] E. G. Stassinopoulos, “Shortcomings in Ground Testing,
Environment simulations, and Performance Predictions for Space
Applications,” RADECS 1991 Proceedings, pp.3-16.
[4] S. Duzellier, R. Ecoffet, “Recent Trends in Single Event Effect
Ground Testing,” ,” IEEE TNS, vol. 43, n°2, pp. 671-677, April
1996.
[5] A.J. Tylka & al., “Single Event Upsets caused by Solar Energetic
Heavy Ions,” ,IEEE TNS, NS43, pp. 2758, Dec. 1996.
[6] J. Barth “Modeling Space Radiation Environment” 1997 IEEE
NSREC short course.
[7] W. Heinrich, “Calculation of LET Spectra of Heavy Cosmic Ray
Nuclei at Various Absorber Depths”, Radiation Effects, vol. 34,
pp.143-148, 1977.
[8] E.G. Stassinopoulos & al. ,“SEU measurements at the BNL test
facility,” Trans. Am. Nucl. Soc., vol. 62, pp. 230-232, 1990.
[9] M.A. Mc Mahan, ‘Radiation Effects Testing at the 88 inch
Cyclotron” RADECS 1999 proceedings, pp. 142-147.
[10] G. Berger & al., “The Heavy Ion Irradiation Facility at CYCLONE-
A dedicated SEE beam line,” 1996 IEEE NREC data workshop, pp.
78-83.
[11] M. Labrunee & al., “Heavy ion component test coordination,”
RADECS 1991 proceedings, pp. 577-581.
[12] M.A. Xapsos, “Applicability of LET to Single Events in
Microelectronic Structures”, IEEE Trans. Nucl. Sci., vol. 39, pp.
1613-1621, Dec. 1992.
[13] D.K. Nichols & al., “update of Single Event failure in power
MOSFETs,” IEEE NSREC 1996 dataworkshop, pp. 67-72.
[14] J. C. Pickel, “Single Event Effects Rate Prediction,” IEEE Trans.
Nucl. Sci., vol. 43, n°2, April 1996.
[15] H. Dussault, “The effects of ion track structure in simulating Single
Event Phenomena,”, Proceedings of RADECS 1993, pp. 509-516.
[16] R. Koga & al., “Comparative SEU sensitivities to relativistic heavy
ions,” IEEE TNS, vol. 45, n°6, pp. 2475-2482, 1998.
[17] P.E. Dodd & al. “Impact of ion energy on Single event Upset,”
IEEE TNS, vol. 45, n°6, pp. 2483-2491, 1998.
[18] S. Duzellier & al. “SEE results using high energy ions,” IEEE
TNS, vol. 42, n°6, pp. 1797-1802, 1995.
[19] R. Ecoffet “Low LET cross section measurements using high
energy carbon beam,” IEEE TNS, vol. 44, n°6, 1997.
[20] R. Koga & al., “SEE sensitivity determination of high density
DRAMs with limited range heavy ions,” IEEE NSREC 2000 data
workshop, pp45-52.
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