M.P. dos Santos

Investigations of titanium oxide films deposited by d.c. reactive magnetron sputtering in different sputtering pressures

Titanium oxide thin films were deposited on glass substrates by the d.c. reactive magnetron sputtering method. The dependence of structural and optical properties of films, and film composition, on the sputtering pressure was studied. The results of the X-ray diffraction show that all films only have the anatase TiO2 phase. At lower sputtering pressure, the film has a preferred orientation along (101) direction. As the sputtering pressure increases, the intensity of the (101) diffraction line decreases gradually. When the sputtering pressure is higher than 2 × 10−2 mbar, the film exhibits an almost amorphous structure. The results of scanning electron microscopy show that the film structure changes from more dense to more porous as the sputtering pressure increases from 2 × 10−3 mbar to 2 × 10−2 mbar. These structure variations in result in the variations in the optical properties. As the sputtering pressure increases from 2 × 10−3 mbar to 2 × 10−2 mbar, the refractive index n and extinction coefficient k (at 500 nm) vary from 2.48 to 2.14 and from 4.06 × 10−3 to 0.59 × 10−3 respectively.

Properties of indium tin oxide films prepared by rf reactive magnetron sputtering at different substrate temperature

Abstract Indium tin oxide (ITO) films were deposited onto the glass substrates at different substrate temperatures (RT-500°C) by rf reactive magnetron sputtering method. The structural, optical and electrical properties of ITO films have been characterized by X-ray diffraction, scanning electron microscopy, optical transmittance and reflectance, sheet resistance and electrical resistivity measurements. The films deposited at low substrate temperature have a very strong (222) diffraction peak which means a preferred orientation along the [111] direction. As the temperature is increased, the (400) diffraction peak intensity increases and results in a preferred orientation along [100] direction for the films prepared at 500°C substrate temperature. The film prepared at 400°C substrate temperature has the lowest electrical resistivity (about 3.7×10 −4 Ω cm).

Study of the structural properties of ZnO thin films by x-ray photoelectron spectroscopy

Abstract X-ray photoelectron spectroscopy (XPS) analysis was performed on ZnO films prepared on glass substrates by DC reactive magnetron sputtering at different substrate temperatures (room temperature to 450°C). In the O 1s spectra two resolved peaks were observed. The lower energy peak, located at 530 eV, corresponds to O-Zn bonding, while the higher energy peak, located at 532 eV, could be assigned to OH(531.5 eV) and/or H 2 O(533 eV) species. As the substrate temperature is increased, the oxygen component located at higher energy decreases. This variation was correlated with the structural properties of the films. The films prepared by DC reactive magnetron sputtering generally have a columnar structure with many pores. In air some of these pores are filled with water and result in the appearance of a higher energy peak in the O 1s spectra. The decrease of the oxygen component located at higher energy indicates the decrease of the porosity of the films. The results obtained by scanning electron microscopy measurements were in agreement with this conclusion.

Direct current reactive magnetron sputtered zinc oxide thin films —the effect of the sputtering pressure

Abstract ZnO thin films were deposited onto glass substrates by d.c. reactive magnetron sputtering from a metallic zinc target. A systematic study has been made on the influence of sputtering pressure in the range from 0.2 Pa to 3 Pa on the film structural and optical properties. At low sputtering pressure (0.2–0.4 Pa), the film was inhomogeneous, non-stoichiometric and had low refractive index and an almost amorphous structure. At high sputtering pressure (0.6–0.8 Pa), the film was homogeneous, stoichiometric and had high refractive index and the crystallinity was improved. As the sputtering pressure was further increased (1–3 Pa), the homogeneity and the refractive index of the film had no clear variation, but the crystallinity of the film went down. As the sputtering pressure was increased from 0.2 Pa to 3 Pa, the transmittance of the film increased and the deposition rate of the film decreased.

Characterisation of ZrO2 films prepared by rf reactive sputtering at different O2 concentrations in the sputtering gases

Abstract Zirconium oxide (ZrO 2 ) films have been prepared by rf reactive magnetron sputtering at different O 2 concentrations in the mixture sputtering gases. The films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and optical spectroscopies. The influence of O 2 concentration in the sputtering gases on the microstructure, residual stress and optical properties of the films has been studied. Also, the effect of loose packing structure caused by the high O 2 gas concentration on the deposition rate has been discussed.

Properties of indium tin oxide (ITO) films prepared by r.f. reactive magnetron sputtering at different pressures

Abstract A set of indium tin oxide (ITO) films has been prepared by r.f. reactive magnetron sputtering at different total sputtering pressures using an indium tin alloy target. The effect of the pressure on ITO films properties have been studied. The pressure is varied from 0.08 to 0.76 Pa. The deposition rate does not show a significant variation with the pressure. The preferred orientation of ITO films change from the [222] to the [440] direction as the pressure is increased from 0.08 to 0.76 Pa. All the films are subject to a compressive stress. The film that prepared at high pressure show a very rough surface. All the films show a high optical transmittance. The film that prepared at low pressure give a low electrical resistivity. The lowest electrical resistivity which we have obtained in this work is about 2 × 10 −3 Ω cm.

Zinc oxide films prepared by dc reactive magnetron sputtering at different substrate temperatures

Abstract The properties of zinc oxide films prepared by dc reactive magnetron sputtering were studied over a range of the substrate temperatures (room temperature to 450°C). The dependence of the structure of the films on the substrate temperature was studied using scanning electron microscopy and X-ray diffraction. The films had a preffered orientation along the (002) crystal plane at room temperature (50°C), a random orientation at 200–300°C and again a preferred orientation along the (002) crystal plane at 350–450°C. The grain size increased as the substrate temperature was raised. In addition, the optical and electrical properties have also been investigated.

Characterization of titanium nitride films prepared by d.c. reactive magnetron sputtering at different nitrogen pressures

Titanium nitride films have been grown onto glass substrates by d.c. reactive magnetron sputtering from a titanium metallic target at different nitrogen partial pressures. The influence of the nitrogen pressure on structural, electrical and optical properties of TiN films was investigated by measuring their X-ray diffraction, scanning electron microscopy, optical reflectance and electrical resistivity. The films show the (111) preferred orientation, the (111) peak intensity decreases as the nitrogen partial pressure is increased. The films have columnar structure and the grain size both along the sample surface and normal to the sample surface increases as the nitrogen partial pressure is increased. The film resistivity has been related with the variation of the film structure. The film, which has high (111) diffraction peak intensity, has high resistivity.

The influence of oxygen partial pressure on the properties of DC reactive magnetron sputtered titanium oxide films

Abstract Titanium oxide thin films were grown on glass substrates by DC reactive magnetron sputtering at various oxygen partial pressures. The films were characterized using X-ray diffraction (XRD), X-ray photelectron spectroscopy (XPS), scanning electron microscopy (SEM) and optical transmittance spectra. The effects of the oxygen partial pressure on the structural and optical properties of titanium oxide films were investigated.

Influence of sputtering pressure on the structure and properties of ZrO2 films prepared by rf reactive sputtering

Abstract Zirconium oxide (ZrO 2 ) films have been prepared by rf reactive magnetron sputtering at different sputtering pressures. It is found that the monoclinic phase is the dominant phase in the films and there is a small fraction of tetragonal phase in the films prepared in the low pressure region. The influence of sputtering pressure on the microstructure, residual stress and optical properties of the films has been studied. The films have been characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and optical spectroscopy.