Chemical vapor desposition of cerium and copper-doped strontium sulfide for applications in thin film electroluminescent devices

The primary objective of this work was to develop and optimize a thermal metal-organic chemical vapor deposition (CVD) process to deposit cerium and copper-doped strontium sulfide (SrS:Ce and SrS:Cu) thin films for electroluminescent (EL) display applications. SrS:Ce and SrS:Cu thin films are promising new electroluminescent materials for flat panel display applications. This is due to their inherent ability to emit blue light in the visible region of the electromagnetic spectrum. CVD is a proven method to deposit high quality films at lower deposition temperatures and higher growth rates than other deposition techniques. However, key reliability and processing issues must be addressed to make CVD SrS:Ce and SrS:Cu a viable technique for flat panel display technologies, especially in view of the need for high brightness films with the proper chromaticity for manufacturing full-color thin film electroluminescent displays.; The present study was carried out in two stages. In a first stage, screening studies were performed to understand the nucleation characteristics of SrS thin films and establish preliminary findings regarding the effects of process parameters on film texture. It was determined that the deposition SrS:Ce and SrS:Cu films that meet target specifications in terms of brightness and efficiency required tight control over film texture, stoichiometry, surface morphology, and purity levels. Such control was achieved by performing second stage systematic studies that employed a full design of experiment (DOE) approach to identify the primary predictors (process parameters) and establish their resulting effects on film properties and associated EL performance.