1063-7397/01/3001- $25.00 © 2001 MAIK “Nauka /Interperiodica”
Russian Microelectronics, Vol. 30, No. 1, 2001, pp. 22–26. Translated from Mikroelektronika, Vol. 30, No. 1, 2001, pp. 27–31.
Original Russian Text Copyright © 2001by Svetlichnyi, Polyakov, Varzarev.
In microelectronics, silicon dioxide ﬁlms are widely
used as insulating, passivating, and masking layers, as
well as gate dielectric in MIS transistors. The doped
ﬁlms serve as diffusion sources and getters [1–3].
High-temperature formation of
pyrolytic decomposition of organosilicone compounds,
is common in fabricating semiconductor structures.
However, high temperatures limit the application of
these techniques in submicron IC technology mainly
because of impurity redistribution and degradation of
contacts and metallization.
Below are approaches aimed at reducing the tem-
(1) The use of reactions with a lower activation
energy and components that are chemically active at
(2) thermal preactivation of molecules outside the
(3) nonthermal activation with catalysts or under the
action of an electromagnetic radiation .
In connection with this, UV-activated low-tempera-
ture deposition of
seems to be a very promising
approach, especially for
processes [3, 5]. Also,
the use of UV radiation improves surface cleaning,
enhances the oxidation rate, and lowers the decomposi-
tion temperature of organosilicone compounds during
ﬁlm growth .
Usually, organosilicone compounds used are
. A relatively new approach in this
ﬁeld is to use tetraethoxysilane (TEOS),
, which allows the growth of
better physical properties along with high conformity
and homogeneity. However, deposition temperatures in
this case are high (650–750
C) , so that this process
has received limited application. Therefore, low-tem-
perature photochemical deposition of SiO
is of certain interest.
An experimental setup for
osition from a TEOS + oxygen mixture was modiﬁed
UVN-62 equipment. Substrates were heated with KG-
220-1000 halogen lamps. The working side of the sub-
strates was irradiated with three DRT-400 UV lamps. A
leak of working gas (TEOS + O
) had the shape of a
torus with outlets facing the substrate center. The inner
diameter of the torus was 10 mm larger than the diam-
eter of the substrate holder to ensure the uniform illu-
mination of the substrate. Such a design of the leak pro-
vides a laminar ﬂow of the gas mixture and, hence,
improves the quality of the ﬁlms grown.
TEOS was supplied into the deposition zone by bub-
bling oxygen through a TEOS-containing thermostati-
cally controlled bubbler. Then, the gas passed through
a ﬂow-rate controller and entered the reaction chamber
toward the leak. The rotation of the sample at 1–2 rpm
during photochemical deposition helps to improve the
uniformity of SiO
thickness. The temperature was
controlled with a thermocouple.
The characteristics of the equipment for low-tem-
perature photochemical deposition are given in Table 1.
In experiments, we used KDB-10 (boron-doped,
cm) polished (100)Si wafers. Before
deposition, each substrate was subjected to standard
processing with the use of extra-pure-grade reagents
and deionized water. To elucidate the effect of process
conditions on the deposition kinetics and ﬁlm proper-
ties, we used experimental procedures allowing the
control of the ﬁlm structure and composition. The elec-
trical properties of the Si/SiO
structure were studied
with a four-probe method and test MOS structures.
These structures employ 0.1- to 0.15-
The Formation of Silicon Dioxide Films
by TEOS Photochemical Decomposition
A. M. Svetlichnyi, V. V. Polyakov, and Yu. N. Varzarev
Taganrog State Radio Engineering University, Nekrasovskii pr. 12, Taganrog, 347928 Russia
Received July 16, 1999
—Silicon dioxide ﬁlms were obtained by TEOS photochemical decomposition. The specially
designed setup is described. A possible decomposition mechanism in the vapor phase is outlined. The suggested
kinetic model of SiO
photochemical deposition from the TEOS–oxygen vapor phase ﬁts experimental data for
temperatures between 300 and 450