Showing 5 results for Thin Film
A. Bahari, M. Roodbari Shahmiri , N. Mirnia,
Volume 31, Issue 1 (6-2012)
Abstract
Recently, high – K materials such as Al2O3 and TiO2 films have been studied to replace ultra thin gate silicon dioxide film. In the present work, these films were grown on the top of Si(100) surface at different temperatures and under ultra high vacuum conditions. The obtained results showed that Al2O3 has a structure better than that of TiO2 and thus can be used as a good gate dielectric for future MISFET (Metal – Insulator- Semiconductor- Field – Effect- Transistors) devices.
A. Khanjani, A. Ghasemi, M. Hadi,
Volume 35, Issue 1 (6-2016)
Abstract
In the present research NdFeB thin films coupled with buffer and capping layer of W were formed on Si/SiO2 substrate by means of RF magnetron sputtering. The system was annealed at vaccum at different temperatures of 450, 500, 550,. 600 and 650 °C Phase analysis was carried out by XRD and it was found that NdFeB was formed without the formation of any kind of secondary phase. The cross sectional and grain size of the thin films were measured by scanning electron microscopy. Morphological studies were performed by atomic force microscopy. Magnetic properties of thin films including coercivity, saturation of magnetization and hysteresis area were evcaluated by vibrating sample magnetometer. It was found that by annealing at 400 °C the amorphous layer was formed.The highest intensity of peaks was formed at 550 °C and with an increase in temperature the intensity was declined. The grain size was increased by temperature and had an impact on the coercivity. With an increase of temperature up to 600 °C, perpendicular coercivity was increased and then by further increase of temperatute, coercivity was reduced. Based on the obtained data the temperature of 600 °C was selected as the optimum annealing temperature for reaching enhanced structural and magnetic feature.
M. Hajfarajzadeh, A. Eshaghi, A. Aghaei,
Volume 37, Issue 4 (3-2019)
Abstract
A TEOS-GPTMS nano-hybrid thin film was deposited on the polymethyl methacrylate (PMMA) substrate by a sol-gel dip coating method. Morphology, roughness and surface chemical bonding of the thin films were evaluated by X-ray diffraction (XRD), field emission scanning electron microscopy(FE-SEM), atomic force microscopy, and Fourier transform infrared spectroscopy methods, respectively. UV-vis spectrophotometer was used to measure the transmittance spectra of the samples. Also, the adhesion and hardness of the coatings were investigated using pencil hardness the adhesion tape test and the test, respectively. XRD results proved that the thin film had an amorphous structure. Also, FE-SEM images indicated that addition of GPTMS to the TEOS yielded a crack-free thin film. Based on the UV-vis spectroscopy results, the transmittance of the polymer substrate in the visible region was increased by the deposition of the nano-hybrid coating. Moreover, the hardness of the PMMA substrate was increased from 3H to 6H by the deposition of the nano-hybrid thin film. Also, tape test confirmed the high adhesion of the nano-hybrid thin film on the PMMA substrate. Consequently, the transparent organic-inorganic GPTMS-TEOS hybrid coating can be used as a scratch resistant coating on the PMMA substrate.
M. Maniei, A. Eshaghi, A. Aghaei,
Volume 38, Issue 2 (9-2019)
Abstract
In this research, MgF2-2%SiO2/MgF2 thin films were applied on a glass substrate. At first, MgF2 thin films with the optical thickness were deposited on the glass slide substrates. Then, MgF2-2%SiO2 thin films were deposited on the glass coated with MgF2 thin films. Finally, the nanocomposite thin films were surface treated by the PFTS solution. Characterization of the thin film was done by X-Ray defractometry (XRD), attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR), UV-Vis spectroscopy, and atomic force microscopy (AFM) techniques. Also, the hydrophobic properties of the samples were investigated by measuring the contact angle of the water. The results showed that the deposition of the six layer MgF2 thin films on the two sides of the glass substrate increased the transmission up to 96.4%. For the glass deposited by MgF2-2%SiO2 nanocomposite thin films, transmission was reduced to 94.4%, with its transmission being higher than the pure glass. Also, the water contact angle (WCA) analysis determined that the contact angle of the water droplet on the MgF2-2%SiO2 nanocomposite thin film coated glass was decreased. On the other hand, the contact angle of the water droplet on the MgF2-2%SiO2 nanocomposite thin film coated glass after modification with the PFTS solution was increased up to 119o. So, MgF2-2%SiO2 nanocomposite thin films could be used as an antireflective and self-cleaning coating on the surface of the optical devices.
E. Mohagheghpour, R. Gholamipour, M. Rajabi, M. Mojtahedzadeh Larijani,
Volume 40, Issue 3 (11-2021)
Abstract
In this study, the amorphous carbon thin films were deposited by ion beam sputtering deposition method on the glass and Ni–Cu alloy substrates. The structural evolution of amorphous carbon and its correlation with the kinetic energy of carbon atoms during the growth of thin film was investigated. The effect of substrate material, deposition temperature, and ion beam energy on the structural changes were examined. Raman spectroscopy indicated a structural transition from amorphous carbon to diamond-like amorphous carbon (DLC) due to an increase in deposition temperature up to 100°C and ion beam energy from 2 keV to 5 keV. The size of graphite crystallites with sp2 bonds (La) were smaller than 1 nm in the amorphous carbon layers deposited on Ni-Cu alloy. The results of residual stress calculation using X-ray diffractometer (XRD) analysis revealed a decreasing trend in the tensile residual stress values of the amorphous carbon thin films with increasing the ion beam energy.
