hard errors are destructive. Soft errors include single event upset (SEU), transient
(SET) and functional interrupt (SEFI). Because the soft errors are non-destructive,
local and temporary, the systems where such phenomena occur can be recovered by
system rebooting. In contrast, hard errors include single event latch-up (SEL), gate
burnout (SEB) and gate rupture (SEGR), which result in permanent failure. Though
a system in which SEL occurred may be recovered by rebooting, SEL is generally
classified as a hard error. Figure 5 shows the classification of SEEs.
The primary cause of these SEEs is the charge generated by energetic particles
striking in a semiconductor. Figure 6 shows an illustration of reverse biased p-n
10
10
10
9
10
8
10
7
10
6
10 5
10
4
10
3
10 2
10
–1
10
–2
10
Individual
Elements
Pb
Pt
Ba
Zr
Fe
Si
O
C
He
H
Even–Z
Elements
Element
Groups
20 30 40 50 60 70
Nuclear Charge (Z)
Nuclear Composition
of Galactic Cosmic Rays
Relative Flux (Si=10 6
)
80 90 100
10
1
(
˜
2 GeV/nuc)
Fig. 4 Relative flux of GCRs by nuclear charge (Z) [7]
Table 1 Classification of radiation effects
Short term
(caused by single ion hit)
Long term
(cumulative effect)
Ionizing energy loss
Single event effects (SEEs)
Total ionizing dose (TID)
Non-ionizing energy loss (NIEL)
–
Displacement damage (DD)
62
K. Takeuchi et al.