IGZO Film Patterning for OLED Work Function Tuning
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Solution Overview
Problem
Existing OLED devices have limited adjustability in the work function of their electrodes, which restricts the increase in light emitting efficiency and involves complex and costly manufacturing processes for AMOLED display devices.
Innovation Solution
The use of indium gallium zinc oxide (IGZO) as the material for either the anode or cathode layers in OLED devices, allowing for a wider range of work function adjustment and simplifying the manufacturing process by forming the TFT active layer and pixel electrode layer from the same IGZO film, thereby reducing production costs and enhancing light emitting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional materials (ITO for anode, Al/Ca/Li/Mg for cathode) are used with constant work functions, then the device structure is simple, but the work function adjustment range is limited and light emitting efficiency cannot be increased
Solution Approach 1:
The patent applies parameter changes by using IGZO material where the work function can be continuously adjusted through controlling the In/Ga/Zn atomic ratio and oxygen content. By varying the composition parameters (In:Ga:Zn = 1:(0.1-1.0):(0.1-1.0) and oxygen partial pressure 10-700 Torr), the work function can be tuned across a wide range, resolving the limitation of fixed work function values in traditional materials
Solution Approach 2:
The patent employs composite material strategy by creating IGZO as a quaternary compound (In-Ga-Zn-O) that combines the advantages of different metals. This composite approach allows simultaneous optimization of work function, stability, and light transmittance properties that cannot be achieved with single-element metals like Al, Ca, Li, or Mg
2Manufacturing precision
If separate processes are used to form TFT active layer and pixel electrode layer, then each layer can be optimized independently, but the manufacture process becomes complicated and production costs increase
Solution Approach 1:
The patent merges the formation of TFT active layer and pixel electrode layer into a single IGZO deposition step. By using one material system (IGZO) for both layers, the patent eliminates the need for separate material deposition processes, simplifying the manufacturing process while maintaining the ability to differentiate layers through post-deposition patterning and selective treatment
Solution Approach 2:
The patent applies universality by using IGZO material that can serve multiple functions: it can form both the TFT active layer and the pixel electrode layer (anode or cathode). This multi-functional material approach reduces the number of different materials needed and simplifies the overall manufacturing process while maintaining optimization capability through compositional control
Data Source
AI summary
Embodiments of the invention disclose an OLED device, an AMOLED display device and a method for manufacturing the AMOLED display device. the AMOLED display device comprises a TFT active layer, a pixel electrode layer and an OLED device; the OLED device comprises a cathode layer and a functional layer, and the pixel electrode layer serves as the anode layer of the OLED device; alternatively, the OLED device comprises an anode layer and a functional layer, and the pixel electrode layer serves as the cathode layer of the OLED device. Moreover, the TFT active layer and the pixel electrode layer are formed from a same IGZO film by a patterning process.