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Sr(Zr0.2 Ti0.8 )O3 dielectric thin film for electroluminescent devices was prepared by in‐line‐type rf magnetron sputtering method using oxide target. Novel phenomenon of periodic concentration fluctuations of the composing ions was observed in SIMS in‐depth profiles. Partial concentration anomaly with Sr deficiency was also observed in the first‐to‐grow region of the film. The periodic concentration fluctuations were confirmed to be ascribed to periodic appearance of Sr(Zr1−x Tix )O3 with x larger than 0.8.

The chemical reaction to form dielectric thin films of Sr(Zr0.2Ti0.8)O3 by an RF magnetron sputtering method using a ceramic target has been investigated. The amount of extracted Sr by water, Zr/Sr atomic ratio and the lattice constant in addition to other electric and optical characteristics of the film were measured to examine the progress of the reaction. As the results, the chemical reaction to form the perovskite type dielectric thin films with the composition described above was found to be well promoted in the sputtering conditions; substrate temperatures above 450°C, sputtering gas pressure at ≈6×10-3 Torr, sputtering gas mixing ratio O2/Ar of ≈3/1, target-substrate distance of 50-60mm, and sputtering power density at ≈4W/cm2, obtaining the good electric and optical characteristics.

Obtention par pulverisation haute frequence. L'oxyde de Pr-Mn a une structure de perovskite. Caracteristiques electriques et optiques

Obtention par pulverisation haute frequence. L'oxyde de Pr-Mn a une structure de perovskite. Caracteristiques electriques et optiques

The relationship between patterning characteristics and other (such as microstructural and electroptical) characteristics which depend on sputtering conditions, especially the substrate temperature and oxygen partial pressure, was investigated in ITO films prepared by the rf magnetron sputtering method. Sputtering conditions that satisfied both the patterning and electroptical characteristics were found to exist and ought to be precisely controlled since the postannealing of ITO films does not necessarily improve the patterning characteristics. The films showing superior patterning characteristics had dense microstructures without pores and simultaneously exhibited fairly low etching rates and low resistivities.

Electric resistance change of indium-tin oxide (ITO) film was investigated when dielectric oxide films such as Sr(Zr0.2Ti0.8)O3 and Y2O3 for an electroluminescent device were deposited on the ITO by the rf magnetron sputtering method using oxide ceramic targets. In order to understand the mechanism of the resistance change, a dc voltage of -70∼+70 V was biased to an ITO film during the sputtering of dielectric oxide films. The resistance of the ITO film became higher in the positive bias region. The cause of the increase in resistance of the ITO films was confirmed to be oxidation by the oxide targets and the sputtering gas. The amount of the resistance change could be qualitatively explained by the ratio of the oxygen introduced into the ITO film and the combined oxygen forming O2 gas at the ITO surface incident to the ITO film at the sputtering of the dielectric oxide films.

Characteristics of ZnS:Mn films prepared by an rf sputtering method for electroluminescent devices were examined in detail; the features were clarified by a comparison with films produced by an electron-beam method. It was found that the incident species to the substrate during sputtering were composed of ZnS, Zn2, Zn2S, MnS and ZnMn in addition to Zn and S atoms; in the case of the electron-beam method, they were composed of Zn and S2. We confirmed that preparative, crystallographic, microstructural , chemical, and eventually electroluminescent characteristics in sputtered ZnS:Mn films were different from those in electron-beam films, according to the fundamental difference of the incident species to the substrate, which affected film growth.

The blackening phenomenon of an indium-tin oxide (ITO) film when Sr(Zr0.2Ti0.8)O3 dielectric film was deposited on it by the rf magnetron sputtering method has been examined by X-ray photoelectron spectroscopy. It was found that the blackening took place in the thin surface layer of the ITO film near the Sr(Zr0.2Ti0.8)O3/ITO interface and originated from preferential reduction of the Sn4+ ion to Sn0 rather than of In3+.

The effects of an oxygen and some metal oxide impurities introduced into the ZnS:Mn film at its postannealing process were examined with respect to the characteristics of an electroluminescent device. Depending on the oxygen pressure at the postannealing, the oxygen either decreases the emission threshold field strength in the ZnS:Mn film or forms an additional insulating film such as ZnSO4. The metal oxide impurities Fe, V, and Co caused a decrease in luminance via a killer effect on the Mn emission center. On the other hand, Ti, In, Na, and V decreased the emission threshold voltage by lowering the emission threshold field strength in the ZnS:Mn film.

In the electroluminescent device laminated with the following thin films, ITO/Sr(Zr0.2Ti0.8)O3/ZnS:Mn/Y2O3/Al2O3/Al, diffusions of In, Sr and Ti ions to the ZnS:Mn film were observed at high postannealing temperature of the ZnS:Mn films. We confirmed that an optimized annealing temperature needed to obtain the highest luminance was located at 450°C, where pronounced diffusions did not take place. The diffusion of the Ti ion into the ZnS:Mn film was considered to affect the performance of the EL device.