Effect of the substrate surface topology and temperature on the structural properties of ZnO layers obtained by plasma enhanced chemical vapour deposition (original) (raw)
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Influence of the processing conditions on the structural properties of ZnO layers obtained by PECVD
Journal of Physics: Conference Series, 2010
The plasma enhanced chemical vapor deposition (PECVD) is a powerful and flexible instrument for depositing thin layers, nanocomposites or nanostructures. In this work ZnO layers have been grown by metal-organic PECVD (RF - 13.56 MHz) on Si wafers. Zn acetylacetonate has been used as a precursor and oxygen as oxidant. The influence of the oxygen content in gas mixture, the total pressure, substrate temperature and ZnO seed layer on the structural properties of the layers deposited on Si wafers has been studied. ZnO layer properties were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD data have shown that all layers are crystalline with hexagonal wurtzite structure. The crystallites are preferentially oriented along c-axis direction perpendicular to the substrate surfaces. The results obtained indicate that by controlling the oxygen content in gas mixture, the total pressure and substrate temperature during the film growth one can control the formation of c-axis phase and the crystallite grain size. Nanorods with good alignment, vertically orientated to the substrate surface can be observed in the layers deposited at low content of O2 in plasma at substrate temperature of 400 oC. Due to their structural characteristics these layers are potential materials for preparing chemical- and biosensors where inherently large surface to volume ratio of structured materials are important prerequisite for enhanced sensitivity.
Structural properties of ZnO layers deposited on glass substrates by PECVD
Journal of Physics: Conference Series, 2012
Thin ZnO layers were grown by metal-organic plasma-enhanced CVD (RF -13.56 MHz) on glass substrates without and with ZnO seed film. The properties of the ZnO layers obtained were studied in dependence of the partial oxygen pressure by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results obtained show that by controlling the partial oxygen pressure during the layer growth one can control the crystallinity and texture of the layers obtained on pure glass substrates. It was found that ZnO layers deposited at low O 2 pressure have well-developed grain structures with a predominant c-axis phase and better crystalline quality than that of the samples obtained at high partial oxygen pressure. In the presence of ZnO seed films, the formation of c-axis phase and its quality are less dependent on partial P O 2 . Nanorods with good alignment and orientated vertically with respect to the substrate surface can be observed in the layers deposited on glass substrates with ZnO seeds and substrate temperature of 400 o C at low content of O 2 in the plasma. This behavior is interpreted in the framework of the so-called preferential nucleation and preferential grain growth.
Plasma enhanced chemical vapor deposition of ZnO thin films
Journal of Non-Crystalline Solids, 2006
Zinc oxide thin films were deposited on silicon and corning-7059 glass substrates by plasma enhanced chemical vapor deposition at different substrate temperatures ranging from 36 to 400°C and with different gas flow rates. Diethylzinc as the source precursor, H 2 O as oxidizer and argon as carrier gas were used for the preparation of ZnO films. Structural and optical properties of these films were investigated using X-ray diffraction, reflection high energy electron diffraction, atomic force microscopy and photoluminescence. Highly oriented films with (0 0 2) preferred planes were obtained on silicon kept at 300°C with 50 ml/min flow rate of diethylzinc without any post annealing. Reflection high energy electron diffraction pattern also showed the crystalline nature of these films. A textured surface with rms roughness 28 nm was observed by atomic force microscopy for the films deposited at 300°C. A sharp peak at 380 nm in the PL spectra indicated the UV band-edge emission.
International Journal of Materials Engineering, 2016
This research paper aims to present the development of low-pressure high-frequency plasma chemical vapor deposition system for preparation of Zinc oxide (ZnO) thin film on silicon wafer, B-doped p-type Si (100) wafer, with powder deposition. The plasma system for this experimental used mixture of argon (Ar) and oxygen (O2) gas at 10 L/min. and 2 L/min., respectively. The ZnO thin film was performed by heating the ZnO powder. The Ar and O2 gas have been heating in pipe with silicone belt heater and micro gas heater. The temperature was controlled by temperature control (PID). The ZnO thin film was investigated by using contact angle meter and scanning electron microscope (SEM) to confirm the formation of ZnO thin film on the substrate. The results from the contact angle meter confirmed that the Si wafer with ZnO thin film showed an increased in hydrophobic property compared to the traditional Si wafer. In addition, the results from SEM confirmed that the formation of ZnO thin film on...
Thin Solid Films, 2006
ZnO thin films were deposited on a-plane alumina by electron cyclotron resonance-assisted CVD method at several substrate temperatures. The crystal orientation of ZnO thin film strongly depended on the substrate temperature. The full width at half maximum of (002) rocking curve improved from 7-of ZnO film deposited at 300 -C to 0.4-of that deposited at 600 -C. The hydrogen impurity in ZnO thin film decreased with increasing the substrate temperature. The behavior of hydrogen impurity is related with the degree of c-axis orientation. D 2005 Published by Elsevier B.V.
Synthesis and Characterizations of ZnO Thin Films Grown by Physical Vapor Deposition Technique
Journal of Applied Science and Technology Trends
In the current study, Zinc oxide (ZnO) thin films have been synthesized over the whole the glass-slide substrate by utilizing the physical vapor deposition (PVD) technique. The Zinc (Zn) seed layer was deposited by heating the high purity Zn powder by using a molybdenum (Mo) boat at 37.503×10-3 Torr vacuum pressure of the PVD chamber. The ZnO thin films were fabricated by oxidation of the Zn seed layer coated glass-slide substrate at 400 °C. The morphological, chemical compositions, crystal quality, structural and optical properties of fabricated ZnO thin film were characterized and studied utilizing several characterization techniques. The results found that the high distribution density, homogenous, uniform, and high-quality ZnO thin film was grown over the entire substrate. The synthesized ZnO thin film with a thickness of 130 nm was grown with high purity and polycrystalline hexagonal-Wurtzite phase of ZnO. The sharp, and dominant diffraction peak was observed at peak position 3...
THE Coatings, 2021
ZnO thin films were synthesized on silicon and glass substrates using the plasma-enhanced chemical vapor deposition (PECVD) technique. Three samples were prepared at substrates temperatures of 200, 300, and 400 °C. The surface chemical composition was analyzed by the use of X-Ray Photoelectron spectroscopy (XPS). Structural and morphological properties were studied by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Optical properties were carried out by UV-visible spectroscopy. XPS spectra showed typical peaks of Zn(2p3/2), Zn(2p1/2), and O(1s) of ZnO with a slight shift attributed to the substrate temperature. XRD analysis revealed hexagonal wurtzite phases with a preferred (002) growth orientation that improved with temperature. Calculation of grain size and dislocation density revealed the crystallization improvement of ZnO when the substrate temperature varied from 200 to 400 °C. SEM images of ZnO films showed textured surfaces composed of grains of spheric...
Preferential growth of ZnO thin films by the atomic layer deposition technique
Nanotechnology, 2008
Preferred orientation of ZnO thin films deposited by the atomic layer deposition (ALD) technique could be manipulated by deposition temperature. In this work, diethyl zinc (DEZn) and deionized water (H 2 O) were used as a zinc source and oxygen source, respectively. The results demonstrated that (10.0) dominant ZnO thin films were grown in the temperature range of 155-220 • C. The c-axis crystal growth of these films was greatly suppressed. Adhesion of anions (such as fragments of an ethyl group) on the (00.2) polar surface of the ZnO thin film was believed to be responsible for this suppression. In contrast, (00.2) dominant ZnO thin films were obtained between 220 and 300 • C. The preferred orientations of (10.0) and (00.2) of the ZnO thin films were examined by XRD texture analysis. The texture analysis results agreed well with the alignments of ZnO nanowires (NWs) which were grown from these ZnO thin films. In this case, the nanosized crystals of ZnO thin films acted as seeds for the growth of ZnO nanowires (NWs) by chemical vapor deposition (CVD) process. The highly (00.2) textured ZnO thin films deposited at high temperatures, such as 280 • C, contained polycrystals with the c axis perpendicular to the substrate surface and provided a good template for the growth of vertically aligned ZnO NWs.
Optical and structural investigation of ZnO thin films prepared by chemical vapor deposition (CVD)
Thin Solid Films, 2002
Transparent and conductive ZnO thin films have been prepared by a method derived from chemical vapor deposition using Zn (C H O ) as Zn source. The deposited thin ZnO layers of ;0.1 mm thickness on Si and InP semiconductor substrates, have 5 7 2 2 been investigated with respect to the crystalline phase by X-ray diffraction (XRD), and surface morphology by atomic force microscopy (AFM). Spectrophotometric measurements in the ultraviolet-visible-near infrared spectral range and optoelectrical measurements of ZnOysemiconductor heterostructures have been performed. ᮊ