Annealing studies on InN thin films grown by modified activated reactive evaporation (original) (raw)
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Characterization of indium nitride films deposited by activated reactive evaporation process
Thin Solid Films, 2003
Indium nitride films are deposited in the presence of nitrogen plasma by ‘activated reactive evaporation (ARE)’ process on silicon substrate maintained at room temperature. Indium powder was evaporated by resistive heating in the presence of nitrogen plasma excited by a radio frequency (RF) power source (13.56 MHz). The refractive index of 2.91 obtained by ellipsometry, was in good agreement with that of the standard value of indium nitride (η=2.9). Observation of the films by scanning electron microscope shows a smooth and pinhole-free surface and the diffraction pattern reveals the polycrystalline nature with characteristics of hexagonal structure. In3d5/2, In3d3/2 and N1s levels X-ray photoelectron spectra are observed at binding energies of 443.4 eV, 451.8 eV and 396.5 eV, respectively, indicating the formation of indium nitride. Fourier transform infrared spectrum of the deposited film shows the presence of InN bond. These results indicate the feasibility of the ARE process for the deposition of indium nitride on silicon 〈100〉 substrate maintained at room temperature.
Deposition of indium nitride films by activated reactive evaporation process – a feasibility study
Applied Surface Science, 2005
Indium nitride (InN) films are deposited by ‘activated reactive evaporation (ARE)’ process using parallel plate coupled nitrogen plasma (radio frequency source of 13.56 MHz) and evaporation of pure indium powder by resistive heating. Depositions are carried out by varying RF plasma power, on n-type silicon 〈1 0 0〉 substrate, maintained at room temperature, at a nitrogen gas pressure of 1.06 × 10−1 Pa (8 × 10−4 Torr). The film's crystallinity was examined by X-ray diffraction (XRD) and topography by scanning electron microscope (SEM). The diffraction pattern shows polycrystalline nature of the deposited films with characteristics of hexagonal structure. XRD peak intensity increases with increase in power. SEM observations show a smooth and pinhole free surface having improved quality of film with hexagonal structure as the power is increased from 60 to 120 W. Primary X-ray photoelectron spectroscopy (XPS) results show binding energies of the In 3d levels and N 1s level matching well with that of stoichiometric InN. Further, the refractive index of the films, measured by ellipsometry, is in the range of η = 2.79–2.91 with the variation of plasma power, which is in good agreement with the standard value for indium nitride (η = 2.9). These results indicate the feasibility of using, ‘activated reactive evaporation (ARE)’ process for indium nitride depositions on silicon 〈1 0 0〉 substrates maintained at room temperature.
Growth of InN thin films by modified activated reactive evaporation
Journal of Physics D-applied Physics, 2008
Indium nitride films have been grown using modified activated reactive evaporation (MARE). The films were grown on glass and silicon substrates at room temperatures, i.e. without any intentional substrate heating. In this technique, the substrates were kept on the cathode instead of the grounded electrode and hence subjected to low energy nitrogen ion bombardment leading to highly c-axis oriented films. The photoluminescence (PL) and Raman spectrum shows significant improvement in the quality of the films compared with conventional activated reactive evaporation. The band gap measured from the room temperature PL was found to be 1.9 eV. Very high growth rates can be achieved in the MARE growth technique. The modification in the activated reactive evaporation technique may have a large impact on the growth of various compounds such as metal oxides.
Growth of InN Nanocrystalline Films by Activated Reactive Evaporation
Journal of Nanoscience and Nanotechnology, 2009
InN films are grown on silicon and glass substrates by radio frequency (rf) activated reactive evaporation. High purity indium (99.99) is evaporated by resistive heating in the presence of nitrogen plasma. X-ray diffraction shows that the film deposited at low rf plasma powers (≤100 W) are indium rich and further increase in the rf power formation of InN take place. The average crystallite size was found varying from 8 nm to 20 nm as the power increases from 200 to 400 W. The diffraction pattern shows the polycrystalline nature of InN films. The band gap obtained from the transmission spectra show an increase in the band gap with the increase in rf power which can be attributed to variation of nitrogen: indium stoichiometry. The Raman spectra shows wurtzite nature of the film and the photoluminescence measurements show a weak peak around 1.81 eV for the film grown at 400 W. Plasma diagnostics has been carried out in order to understand the role of active species in the process. The large shift in the band gap is attributed to Moss-Burstein shift and presence of residual oxygen in the film.
Carrier transport in InxGa1−xN thin films grown by modified activated reactive evaporation
Applied Physics Letters, 2011
In the present work, we report the temperature dependent carrier transport properties of In x Ga 1Àx N thin films in the entire composition range grown by modified activated reactive evaporation. The carrier transport in these degenerate semiconductors is controlled by impurity band conduction. A transition from metallic to semiconducting type resistivity was observed for indium rich films. The semiconducting behavior originates from electron-electron interaction and weak localization, whereas higher temperature scattering contributes to the metallic type resistivity. A transition of resistivity behavior from the quantum phenomena to the classical Arrhenius approach was observed for x ¼ 0.12 film.
The effects of cap layers on electrical properties of indium nitride films
Applied Physics Letters, 2010
The unintentional n-type doping in the indium nitride thin films was investigated. The electron density decreases from 3.5ϫ 10 19 to 9 ϫ 10 18 cm −3 and the mobility increases from 4 to 457 cm 2 V −1 s −1 when the thickness increases from 50 to 350 nm. This can be explained by assuming the film consists of a surface accumulation layer and a bulk layer. It was found that the accumulation layer can be eliminated by capping the surface with silicon nitride, GaN or zinc nitride of 2 nm each, respectively; while an AlN cap layer will cause the formation of two-dimensional electron gas at the AlN/InN interface.
Indium nitride (InN) thin films were deposited on Si (111) substrate by plasma-assisted reactive evaporation with a variable radio frequency (RF) power supply. The effects of RF power on the structural, morphological, and optical properties of the films were investigated by X-ray diffraction analysis, scanning electron microscopy, energy-dispersive X-ray analysis, UV-vis transmittance, and micro Raman spectroscopy. The electrochemical behaviors of the InN thin films were investigated in 0.1 M KOH electrolyte towards electrochemical water splitting. Linear sweep voltammograms revealed that the anodic current decreases by increasing RF power for the growth of InN thin films. The charge transfer dynamics between the InN thin film and electrolyte interfaces during the electrochemical process were studied using electrochemical impedance spectroscopy (EIS). Variations in donor density and flat band potentials of the InN thin films were deduced from Mott-Schottky plots. Further, the electrocatalytic behavior of InN thin films was investigated with a K 3 [Fe(CN) 6 ] redox probe. The good electrochemical behavior of InN thin films showed that this material could be a potential candidate for water splitting application.
Influence of fabrication steps on optical and electrical properties of InN thin films
Semiconductor Science and Technology
This paper reports on a case study of the impact of fabrication steps on InN material properties. We discuss the influence of annealing time and sequence of device processing steps. Photoluminescence (PL), surface morphology and electrical transport (electrical resistivity and low frequency noise) properties have been studied as responses to the adopted fabrication steps. Surface morphology has a strong correlation with annealing times, while sequences of fabrication steps do not appear to be influential. In contrast, the optical and electrical properties demonstrate correlation with both etching and thermal annealing. For all the studied samples PL peaks were in the vicinity of 0.7 eV, but the intensity and full width at half maximum (FWHM) demonstrate a dependence on the technological steps followed. Sheet resistance and electrical resistivity seem to be lower in the case of high defect introduction due to both etching and thermal treatments. The same effect is revealed through 1/f noise level measurements. A reduction of electrical resistivity is connected to an increase in 1/f noise level.