Silicon carbide (SiC) films were prepared by single and dual-ion-beam sputtering deposition at room temperature. An assisted
Amorphous semiconductor alloys are of technological importance for electronic and
optoelectronic device application. Amorphous silicon carbide (
This letter reports the growth of SiC thin films at room temperature using dual-ion-beam
sputtering deposition (DIBSD), a method that has been used to grow many
different types of films. Recently, it has also been shown that ion-assisted
techniques can greatly improve the adhesion by minimizing
the total stress at the interface and compactness of the coatings despite
the higher optical absorption near the bandgap of the material [
SiC films were deposited by employing a DIBSD system at room temperature. A DIBSD system consists of a focused
Kaufman ion source (main ion source) and a broad-beam Kaufman ion source (assisted-ion source). The Ar gas as pure as
99.999% was used for source gas and for ion-beam generation. Main ion source of 10 cm diameter with the incident angle
of 45° served as a sputtering ion source. Normal sintered high-purity SiC target was used as a sputtering target. The
sputtering chamber was evacuated to
The films were studied by scanning electron microscopy (SEM) using Hitachi S-4700 equipped with energy dispersive spectroscopy (EDS), for their morphology and composition, respectively. The bonding configurations and the structure were measured by TEM (Hitachi H600A-II), FTIR (Niolot AVATAR 360), and Raman spectra which were obtained in the backscattering configuration between 200 cm−1 and 1800 cm−1 by JY-HR800 using an argon ion laser at a wavelength of 514 nm. All the measurements were conducted at room temperature.
During DIBSD, the assisted ion beam
has been utilized to significantly enhance and control the properties of the
film. In order to compare the characteristics of films prepared by DIBSD, IBSD,
which did not use assisted ion beam to irradiate the substrate, was used to
form SiC film. Figure
The TEM micrographs of the sample with 150 eV ion-beam irradiated.
At low resolution, the top SEM
micrograph of a film prepared on Si substrate nonirradicated (sample a) and irradicated
by 150 eV ion beam (sample b) is shown in Figures
(a) Top-, and (b) cross-sectional SEM micrographs of the sample prepared on Si with nonirradicated, (c) top-, and (d) cross-sectional SEM micrographs of the sample irradiated by 150 eV ion beam.
The EDS was only used to measure the proportion of Si and C in our films grown on KBr substrates. The composition uniformity in the film was studied by analyzing several points (with 1 mm2 analysis area) over the surface of the sample. EDS analyses indeed showed that all the films consist of Si and C. The proportion in sample a is Si : C = 9 : 11 (at.% ratio), nevertheless it decreases to 2 : 3 with ion-beam irradicated in sample b. It indicates that all the films are C excess. The main source ion beam sputters the SiC target, then the sputtering particles deposit on the substrate, which include Si, C, and SiC atoms. At the same time, the assisted-source ion beam sputters the deposition, and the secondary ion sputtering rate of Si ion is higher than that of C ion in the films. The increasing of the proportion of C atom might be attributed to resputter on as-deposition film, which maybe due to the sputtering rate of Si ion is higher than that of C ion.
The FTIR is a powerful tool to investigate the
bonding structure in
The FTIR spectra of the films on KBr substrates (a) with nonirradicated (b) with 150 eV ion-beam irradiated.
Although FTIR is high efficiency of Si–C band, it is low
efficiency of Si–Si and C–C bonds. However, Raman spectra are optimum for
researching identic atomic polar bonds, such as Si–Si and C–C bands. So, we
used Raman spectra to analyze the changes of Si–Si and C–C bands. The Raman
spectra from these samples are characterized by the presence of bonds
characteristic of amorphous material, in the 200–600 cm−1 and 1300–1600 cm−1 spectral regions. This
can be seen in Figure
The Raman spectra of the films on Si substrates (a) with nonirradicated (b) with 150 eV ion-beam irradiated.
After assisted ion-beam irradicated, the
SiC films were prepared by single and dual-ion-beam sputtering deposition at room
temperature. The microstructure and optical properties of nonirradicated and assisted ion-beam irradicated films
have been characterized by TEM, EDS, SEM, FTIR, and Raman spectra. The films exposed to a low-energy
assisted ion-beam irradicated during sputtering from a SiC target
have exhibited smoother and compacter surface topography and different
optical behavior than the films deposited with nonirradicated.
With assisted ion-beam irradicated, the density of the Si–C bonding in the film
has increased. At the same time, the excess C atoms or the size of the
This work is supported by the National Natural Science Foundation of China (No. 10275047 and No.10575073) and the Natural Science Foundation of Jiangsu Province of China (No.03KJB140116). This work is also partially supported by Hubei Key Laboratory of Plasma Chemistries and Advanced Materials (Wuhan Institute of Technology).