1063-7397/02/3105- $27.00 © 2002 MAIK “Nauka /Interperiodica”
Russian Microelectronics, Vol. 31, No. 5, 2002, pp. 295–304. Translated from Mikroelektronika, Vol. 31, No. 5, 2002, pp. 350–360.
Original Russian Text Copyright © 2002 by Gorlov, Litvinenko.
It is known that semiconductor devices experiencing
ionizing radiation, such as neutrons or gamma rays, or
electrostatic discharge (ESD) may suffer from two
types of damage . Some damages lead to cata-
strophic failure, whereas the others show up as tolera-
ble variations in electrical parameters. In the latter case,
radiation-induced charges undergo redistribution and
annihilation as time passes. This process is termed
annealing, since it can also be caused by heating. It is a
well-understood phenomenon .
The existence of radiation-damage annealing sug-
gests that ESD damages may exhibit the same effect. A
number of experiments were conducted to test the
hypothesis. It has been found that the annealing of ESD
damages is indeed possible: electrical parameters may
recover totally or partially if the device is kept at room
temperature or subjected to heating or electrical stress-
Thus, it is of interest to compare the annealing
mechanisms of radiation damages with those of ESD
The annealing of radiation damages in semiconduc-
tor devices usually follows one of three different
approaches: rapid annealing, slow annealing, or ther-
mal annealing . With rapid annealing, it takes little
time for the device to recover. Slow annealing proceeds
at room temperature. Thermal annealing implies ele-
Other types of annealing have also been reported.
For example, the device may be subjected to a symmet-
rical high-frequency electromagnetic ﬁeld  or bias–
temperature stressing .
Rapid annealing is usually performed at room tem-
perature or lower. The latter case is exempliﬁed by the
work of Winokur and Boesch, Jr., . They experi-
mented on MOS capacitors irradiated with 4-
pulses of 13-MeV electrons with a dose of 2
at 79 K (Fig. 1). Annealing was observed at tempera-
tures higher than about 130 K. For this level, annealing
time is about 800 s. At 300 K, the process is virtually
completed in 0.1 ms.
The rapid annealing of MOS structures is attribut-
able to the transfer of radiation-generated holes toward
/Si interface. Most of them reach the interface
in less than 1 s, especially when the electric ﬁeld in the
insulator is higher than 10
V/cm. At the interface, some
holes are trapped and may be subsequently annealed.
Irradiation may also produce interface states and lateral
nonuniformities, which can be eliminated by slow
Rapid annealing is characterized by the annealing
factor, i.e., the total number of currently existing dam-
ages divided by that of stable damages. The annealing
factor depends on irradiation temperature and the prop-
erties of the material, especially carrier concentration.
For example, with the pulsed neutron irradiation of sil-
icon, increasing the electron concentration from
was shown to decrease the annealing factor
from 8 to 1.75, the latter determined 10
s after a
pulse . This is linked to a change in damage states,
which affects the rate of damage clustering during irra-
diation and annealing.
The annealing factors of bipolar ICs were measured
to lie within the range 1.5–2 for time intervals of 0.001
to 0.1 s under normal conditions . At room tempera-
ture, annealing is virtually completed in 10 to 1000 s
Slow annealing is usually employed in combination
with other types of annealing. It serves as an intermedi-
ate stage between different steps of thermal annealing.
An example is the work of Buchman . That
experimental study addresses the effect of annealing on
interface-state charges in the context of n-channel
FETs. They were irradiated at a dose rate of
300 krad(Si)/h to a total dose of 90 krad(Si) and then
subjected to slow annealing at 25
C for 1500 h, with
+9.7 V applied to the gates. Afterward, the devices were
Annealing of Radiation and Electrostatic-Discharge Damages
in Semiconductor Devices
M. I. Gorlov and D. A. Litvinenko
Voronezh State Technical University, Voronezh, Russia
Received August 17, 2001
—Categories and mechanisms of radiation-damage annealing in semiconductor devices are discussed.
The annealing of electrostatic-discharge damages, a phenomenon discovered by the authors, is investigated
experimentally. It is shown that methods for annealing the latter damages can be categorized in the same way.