Fabrication and Characterization of VO_2 Thin Films by Direct Current Facing Targets Magnetron Sputtering and Low Temperature Oxidation

Low valence vanadium oxide(VO2-x) thin films were prepared on SiO2/Si substrates at room temperature by direct current facing targets reactive magnetron sputtering, and then proc- essed through rapid thermal annealing. The effects of the annealing on the structure and phase transition property of VO2 were discussed. X-ray photoelectron spectroscopy, X-ray diffraction tech- nique and Fourier transform infrared spectroscopy were employed to study the phase composition and structure of the thin films. The resistance-temperature property was measured. The results show that VO2 thin film is obtained after annealed at 320 ℃ for 3 h, its phase transition tempera- ture is 56 ℃, and the resistance changes by more than 2 orders. The vanadium oxide thin films are applicable in thermochromic smart windows, and the deposition and annealing process is compatible with micro electromechanical system process.

Origin of Initial Current Peak in High Power Impulse Magnetron Sputtering and Verification by Non-Sputtering Discharge

A non-sputtering discharge is utilized to verify the effect of replacement of gas ions by metallic ions and consequent decrease in the secondary electron emission coefficient in the discharge current curves in high-power impulse magnetron sputtering （HiPIMS）. In the non-sputtering discharge involving hydrogen, replacement of ions is avoided while the rarefaction still contributes. The initial peak and ensuing decay disappear and all the discharge current curves show a similar feature as the HiPIMS discharge of materials with low sputtering yields such as carbon. The results demonstrate the key effect of ion replacement during sputtering.

Preparation and properties of tungsten-doped indium oxide thin films

Tungsten-doped indium oxide (IWO) thin films were deposited on glass substrate by DC reactive magnetron sputtering. The effects of sputtering power and growth temperature on the structure, surface morphology, optical and electrical properties of IWO thin films were investigated. The thickness and surface morphology of the films are both closely dependent on the sputtering power and the substrate temperature. The transparency of the films decreases with the increase of the sputtering power but is not seriously influenced by substrate temperature. All the IWO thin film samples have high transmittance in near-infrared spectral range. With either the sputtering power or the growth temperature increases, the resistivity of the film decreases at the beginning and increases after the optimum parameters. The as-deposited IWO films with minimum resistivity of 6.4 10 4 cm were obtained at a growth temperature of225 C and sputteringpower of 40 W, with carrier mobility of 33.0 cm 2 V 1 s 1 and carrier concentration of 2.8 10 20 cm 3 and the average transmittance of about 81% in near-infrared region and about 87% in visible region.

Behaviour of Ti Based on Si(111) Substrate at High Temperature in Oxygen

The behavior of Ti based on Si（lll） in oxygen under high temperatures（700 ℃, 800 ℃ , 900 ℃ , I 000 ℃ and 1 100℃） is reported. X-ray diffraction（XRD） and Fourier transform infrared spectroscopy （FTIR） are used to analyze the structure and composition of the samples annealing at different temperatures in oxygen ambience. It is found that raising temperature is helpful to the formation of both TiSi2 and TiO2 and helpful to the diffusion of Ti to Si substrate.

Preparation of ZnO Thin Films on Free-Standing Diamond Substrates

Highly c-axis-oriented ZnO films were deposited successfully on the nucleation sides of free-standing diamond （FD） films by the direct current （DC） magnetron sputtering method. The effect of the sputtering parameters, such as power, gas pressure and sputtering plasma composition of Ar-to-O2, on the properties of ZnO thin films was investigated in detail. X-ray diffraction （XRD） measurements showed that, at a sputtering power of 200 W, gas pressure of 0.5 Pa and an Ar-to- O2 composition of 1：1, a higher intensity of the （002） diffraction peak and a narrower full width at half maximum （FWHM） were detected which meant high c-axis orientation and high quality of the ZnO films. To improve the quality of the ZnO film, a thin ZnO layer was pre-grown as a homo-buffer layer. XRD measurements showed that this buffer layer had a beneficial effect on the structural and morphological properties of the post-grown ZnO film.