ISSN 10637397, Russian Microelectronics, 2011, Vol. 40, No. 6, pp. 379–382. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © A.V. Dunaev, S.A. Pivovarenok, S.P. Kapinos, A.M. Efremov, V.I. Svettsov, 2011, published in Mikroelektronika, 2011, Vol. 40, No. 6, pp. 413–417.
Chlorine and chlorinecontaining gases are widely
used in microelectronics technologies for plasma
chemical etching of series of semiconducting materi
als, including arsenide gallium, aluminum, and cop
per [1–2]. One of the most promising chlorinecon
taining gases utilized as a plasmaforming reagent is
hydrogen chloride that gives a possibility of anisotropic
polished etching of gallium arsenide at technologically
acceptable rates. It is natural that the plasmachemical
etching used as a pictureforming method requires the
development of a simple and reliable control method in
order to obtain information about process kinetics. At
present, emission spectroscopy is one of the most
promising methods for studies of plasmachemical
reactions to obtain absolute and relative concentrations
of reactive species, as well as of etch products directly in
the reaction zone in the real time scale .
This paper is devoted to the study of HCl plasma
etching of gallium arsenide under varying process con
ditions by an emission spectroscopy technique.
A directcurrent glow discharge was created in a
cylindrical flowinggas reactor (inner diameter is
3.4 cm, discharge region being 40 cm long) made of
C49 glass to study the interaction between HCl
plasma and GaAs. The ranges of the external plasma
parameters were as follows: discharge currents of 10–
60 mA, pressure of 20–100 Pa, and a gas flow rate of
at normal conditions. Hydrogen chloride
has been obtained by the chemical exchange reaction
between sodium chloride and sulfuric acid . The
pressure and gas flow rate were measured by a U
forming oil monometer and capillary rheometer,
Specimens in the form of polished GaAs pieces
with a thickness of 400 μm and area of 1 cm
located on a temperature controlled holder within the
zone of a positive discharge column under floating
voltage. The etch rates were determined by weighing
the specimen before and after the process, using a
g) analytical balance.
The surface of semiconducting samples was con
trolled by a Solver P47Pro atomicforce microscope,
having a scanning area resolution of
minimal scanning step 0.006 nm.
The temperature of the neutral species was deter
mined by solving the heatbalance equation , using
the experimental temperature data of the reactor’s
external wall. The electric field strength measure
ments were made with a probe method. The HCl
plasma emission spectra were measured in the 300–
1000 nm wavelength region by a fiberoptical
AvaSpec20482 spectrometer equipped with photo
electric signal registration and computing systems.
The identification of the spectra has been carried out
using reference books [6, 7].
RESULTS AND DISCUSSION
Figure 1 shows the emission spectrum of HCl
plasma etching gallium arsenide. The experimental
results have shown that the HCl plasmaforming gas
emission spectrum in the given wavelength range con
sists only of atomic components. The spectrum con
tains two groups of atomic chlorine lines. The first
Spectral Study of HCl Plasma Etching of Gallium Arsenide
A. V. Dunaev, S. A. Pivovarenok, S. P. Kapinos, A. M. Efremov, and V. I. Svettsov
Ivanovo State University of Chemistry and Technology, Ivanovo, Russia
email: firstname.lastname@example.org; email@example.com; firstname.lastname@example.org
Received September 2, 2010
—Chlorinecontaining gases are widely used in etching series of materials. In this field, hydrogen
chloride is one of the most promising plasma reagents. In this paper, emission spectroscopy techniques have
been applied to study an etching of gallium arsenide in HCl plasma. The gas emission spectrum consists only
of atomic components. The excitation of atoms is carried out with an electron impact, while their collapse is
accompanied by emission deactivation. The control of the etching process can be performed spectrally using
the intensities of the gallium monochloride and gallium resonant lines. The induction period of about 1 min
is observed in the spectral and gravimetric kinetic curves of etch gallium arsenide, but it is absent in samples
previously subjected to etching.
: emission spectroscopy, plasmachemical etching, hydrogen chloride, arsenide gallium.
IN MICRO AND NANOELECTRONICS