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Abstract
Two different 代写留学生论文phases of BaAl2S4:Eu thin films have beenobtained by reactive RF magnetron sputtering of BaxAl:Eu alloytargets. Single-phased films of either form can be selectivelyproduced over a large area. Both phases are capable ofproducing bright and efficient thin film electroluminescence buthave slightly different emission characteristics and quitedifferent electrical and aging properties. Devices made withthese phosphor films on iFire thick dielectric substratesproduced ac EL luminance of L60over 1000 cd/m2at 240 Hz(light pulses) and peak efficiency over 1 lm/W for the α phase,and over 800 cd/m2and 0.9 lm/W for the β phase. Theprocesses have been scaled to 34”-diagonal display panels on apilot production tool.

1. Introduction
Europium-doped barium thioaluminate based on BaAl2S4:Eu iscurrently the most efficient blue phosphor for inorganic thin filmelectroluminescence (TFEL). With intensive development in thepast few years since its re-discovery in 1999 [1], high luminanceblue EL has been obtained using a multi-source electron-beam(E-beam) evaporation technique and successfully applied to thefabrication of 17” diagonal-sized displays [2,3]. However, E-beam evaporation was an inefficient batch process that was notconsidered suitable for mass productions; it was also not veryreproducible and encountered difficulties to make phase-purethin films over large areas.

The sputtering technique for depositing thin films of thecomplex ternary thioaluminate phosphor has also beendeveloped on a smaller sputtering system over the years withvarious single or multi-target configurations [4,5,6]. When itcomes to scaling for large size panels, iFire has chosen thesimplest approach using single alloy targets based on BaxAl:Eu.

In this work, iFire has successfully developed a technologybased on reactive sputtering using BaxAl:Eu alloy targets in anH2S-argon gas atmosphere and proper annealing techniques toallow the fabrication of single-phased thin film phosphors basedon BaAl2S4:Eu with high luminance and efficiency comparablewith the best results achieved by multi-source E-beamevaporation. The techniques have been demonstratedsuccessfully on 34” panels on a pilot production scale.

2. Experimental
The thioaluminate phosphor layer was deposited on 2x2 squareinch glass substrates by RF magnetron sputtering usingBaxAl:Eu alloy targets in an H2S-Ar gas mixture onto standardiFire thick dielectric substrates. The Eu doping concentration istypically 3~5 at% on the basis of the Ba metal. Rectangulartargets have been used with 121 mm wide and 560 mm long in aload-locked CPA2000 system capable of handing 17” panels, or135 mm wide and 1070 mm long in an ULAVC SCV-850 G2system. The SCV-850 G2 tool is a fully automated state of theart multi-chamber and multi-target sputtering unit capable ofpilot scale production of 34” panels.

As-deposited films were amorphous and moisture-sensitive.Panels were unloaded in dry air quickly and then loaded into amuffle-type furnace (ULVAC FCS-2000) for annealing to formthe phosphor layer. Two different annealing methods wereinvestigated. The first was a simple one step anneal in pure drynitrogen with a proper ramp up and a soak at the peaktemperature; the second, called air-pulse anneal, involved twodiffer本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。