ZnS : TbOF thin films sputter deposited from a single versus separate, ZnSand TbOF targets

Thin film ZnS:TbOF electroluminescent (EL) phosphors were radio frequency m agnetron sputter deposited from either a single pressed powder ZnS:TbOF (1. 5 mole % of Tb) target, or two separate sources consisting of a chemical va por deposited grown, undoped ZnS target and a ThOF pressed powder target. F rom two separate ZnS and ThOF targets, the maximum EL brightness at 40 V ab ove the threshold voltage (B-40) was 44 cd/m(2) with a Tb+3 concentration b etween 3 and 4 mole %. From a single pressed powder ZnS:TbOF target, the ma ximum B-40 was 89 cd/m(2) and the Tb+3 concentration in the film was about 4 mole %. X-ray diffraction and transmission electron microscopy analyses s how that films deposited from a single ZnS:TbOF target had a better crystal linity and larger grain size. The lower brightness and poorer crystallinity in the film deposited from two separate ZnS and ThOF targets were attribut ed to damage from negative ion resputtering. (C) 2001 American Vacuum Socie ty.