22.2: Invited Paper: Sputtered Molybdenum‐Oxide for Anti‐Reflection Layers in Displays: Optical Properties and Thermal Stability. (28th November 2018)

• Record Type: Journal Article
• Authors: Schmidt, Hennrik; Koestenbauer, Harald; Koestenbauer, Judith; Linke, Christian; Franzke, Enrico; Winkler, Joerg
• Is Part Of: Digest of technical papers. Volume 49(2018)Supplement 1
• Page Start: 225
• Page End: 229
• Publication Date: 2018-11-28
• Subjects: Sputter Deposition -- Molybdenum -- Oxide -- Ceramic Target -- Low Reflectance -- Narrow Bezel; Information display systems -- Congresses; 621.3815422
• DOI: 10.1002/sdtp.12688
• Languages: English
• ISSNs: 0097-966X

Abstract

Abstract : Molybdenum (Mo) is commonly used for thin film transistor (TFT) metallization in displays. Apart from its outstanding electronic and adhesive properties in the metallic form, it also possesses stable oxidation states, including sub‐stoichiometric oxides. Depending on the amount of oxygen, the properties can be widely tuned and oxygen‐deficient MoO3‐y films can be electrical conducting and optically absorbing, making them suitable candidates for integration as low‐reflection coatings for on/in cell touch, black matrix on array, narrow bezel, or TFT metallization. Deposition of these oxides by fully reactive sputtering from metal targets implies several problems such as lateral inhomogeneities on large substrates (>G5) and difficult control of oxygen flow. To avoid these obstacles, DC‐ sputtering from ceramic Molybdenum oxide targets without the addition of oxygen gas is proposed. In our work, we show the non‐reactive DC‐sputtering of MoOx:TaOx in a stable and reliable process with deposition rates of up to 180 nm/min. Further on, the electrical, optical, and structural properties of the resulting films are studied. The reflectance of light from external sources and the resulting color impression of the dark layer coatings is investigated on different substrates. The color coordinates of the film can be tuned by the layer thickness, the type of covered metal layer (e.g. Cu, Al, Mo), as well as composition of the oxide. From a process stability point of view, we discuss changes during additional annealing steps, and show structural changes at elevated temperatures.