Zhongxiao Song

Effect of thermal annealing on the properties of transparent conductive In–Ga–Zn oxide thin films

Amorphous In–Ga–Zn oxide (IGZO) thin films were prepared using radio frequency magnetron sputtering at room temperature. Upon thermal annealing at temperatures even up to 500u2009°C, the amorphous characteristics were still maintained, but the electronic properties could be considerably enhanced. This could be ascribed to the increased optical band gap and the increased oxygen vacancies, as corroborated by the microstructure characterizations. In addition, the surface became smoother upon thermal annealing, guaranteeing good interface contact between electrode and a-IGZO. The optical transmittance at 400–800u2009nm exceeded 90% for all samples. All in all, thermal annealing at appropriate temperatures is expected to improve the performances of relevant a-IGZO thin film transistors.

Application of Zr-Si film as diffusion barrier in Cu metallization

The diffusion barriers performance of Zr-Si film in Cu/Si contacts has been investigated. Cu/Zr-Si/Si contact system was deposited by using radio frequency reactive sputtering technique. Annealing studies for Cu/Zr-Si/Si were then carried out in nitrogen to investigate Cu diffusion and barrier film crystallization. The contact system was characterized by using four-point probe sheet resistance measurements, X-ray diffraction, scanning electron microscope, and Auger electron spectroscopy (AES), respectively. It is observed that the sheet resistance of Cu/Zr-Si/Si contact system is lower than that of as-deposited specimens even after annealing at 700°C. The Cu/Zr-Si/Si contacts tolerated annealing at 800°C for an hour without structural change of the barrier. AES depth profiles of the annealed Cu/Zr-Si/Si samples are similar to each other and have no intermixing evidence. Zr-Si was found to be a promising diffusion barrier material for Cu metallization.

Tuning the electronic properties in TaNx/Ag nanocomposite thin films

The temperature coefficient of resistance (TCR) of TaNx/Ag nanocomposite thin films could be substantially tuned by changing the components, even down to zero. In the work of this paper, it is unexpectedly found that the concentration of silver incorporation in the TaNx/Ag thin films could be controlled over a broad range from 5.4 at% to 31.14 at% through changing the N2 partial pressure during magnetron sputtering. In particular, the near-zero TCR of −15 ppm K−1 and the highest resistivity of 6038 μΩ cm were obtained in the TaNx/Ag thin films with 12.39 at% Ag. The high resistivity can be attributed to the low carrier density as a result of recombination of holes in the TaNx matrix and electrons in Ag. The composites changes from p-type to n-type at a higher Ag component. The results highlight a new approach to obtain high-performance thin films with zero TCR.

Characterization and tribological behavior of TiAlN/TiAlCN multilayer coatings

Effects of partial pressure of methane on deposition rate, hardness, bonding strength and friction coefficient of TiAlN/TiAlC0.37N0.63 multilayer coating were investigated. The TiAlN coating was deposited at a N2 flow rate of 70 sccm, and TiAlC0.37N0.63 coating were deposited at a N2 flow rate of 35 sccm and a CH4 flow rate of 35 sccm. TiAlN/TiAlC0.37N0.63 multilayer coatings with different modulation periods but the same total thickness of 3.56 μm were deposited on high speed steel substrates using multi-arc ion plating technology. Microhardness and tribological measurement show that the multilayer coating with a modulating ratio of 1:1 and a modulation period of 68 nm had a hardness of 2793.9 HV0.10, an excellent bonding strength of 52N and the minimum friction coefficient of 0.46 and a relatively low wear rate.

Surface-conduction electron emission from W-Mo-Si thin film

This investigation proposes to deposit a ternary material W-Mo-Si as the conductive films for surface-conduction electron emitters. The components of this ternary film can be controlled by changing the sputtering targets and adjusting the sputtering power of the different targets. This study mainly analyses the electron emission of the co-sputtering using a W-Mo-Si target and Mo target. The micro-analysis about the W-Mo-Si film structure after the electro-forming process is carried out with SEM. Results show that there are many anomalous nanoparticles, electrons can tunnel between the nanoparticles and then be attracted by the anode voltage as the emission current.

Influence of oxygen partial pressure on microstructure and discharge properties of Mg-Zr-O protective films deposited by magnetron sputtering

Mg–Zr–O protective films for plasma display panels were deposited on soda-lime glass substrates by magnetron sputtering. The effects of oxygen partial pressure on both the discharge properties (i.e., firing voltage Vf, minimum sustaining voltage Vs, and memory coefficient MC) and the microstructure of the Mg–Zr–O films were investigated. The results show that the deposited Mg–Zr–O films retain the NaCl-type structure as the pure MgO crystal and the doped Zr exists in the form of Zr4+ substitutional solid solution in MgO crystal lattice. The grain of the films is very fine and the mean grain size is about 7nm. As the oxygen partial pressure increases from 0.06to0.12Pa, the Zr content increases and surface roughness of the films decreases. However, when oxygen partial pressure further increases, the film shows a decrease in Zr content and an increase in surface roughness. At oxygen partial pressure of 0.12Pa, the Mg–Zr–O film has the lowest Vf and Vs and the largest MC, exhibiting the best discharge propert...

Electronic structure variation during aging for Mg-Zr-O protective films in alternating current plasma display panel

The variation in both the discharge characteristic and microstructure during aging for Mg–Zr–O protective films was investigated. In the aging process, the firing voltage and the minimum sustain voltage were reduced by 18 V and 10 V, respectively. Meanwhile, the results of x-ray photoelectron spectroscopy (XPS) measurement revealed that the valence band edge of Mg–Zr–O protective films was slightly shifted to a low binding state and the density of states for valence bands was increased. The electronic structure variation related to the changes in crystal structure had an obvious influence on the improvement of discharge characteristic of Mg–Zr–O films.