N-Type Oxide Semiconductor Coating for Stable Low-Temperature TFT Films
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Solution Overview
Problem
Current methods for forming n-type oxide semiconductor films, such as IGZO, face challenges in achieving uniformity and stability due to high process costs and difficulties in reducing oxygen vacancies, leading to instability in film properties.
Innovation Solution
A coating liquid comprising specific elements like Sc, Y, Ln, B, Al, Ga, In, and Tl, along with Group 4-16 elements, dissolved in a solvent, which allows for the formation of stable n-type oxide semiconductor films with controlled volume resistivity and carrier density at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum processes (sputtering or laser abrasion) are used to form oxide semiconductor films, then film uniformity and stability can be achieved, but process cost increases and device complexity increases
Solution Approach 1:
The patent replaces vacuum-based physical deposition processes (sputtering, laser abrasion) with a liquid-phase coating process. The coating liquid containing metal organic compounds is applied to the substrate and then heated to form the oxide semiconductor film, eliminating the need for complex vacuum equipment while achieving stable films
Solution Approach 2:
The patent changes the chemical composition parameters of the coating liquid by incorporating specific metal organic compounds and additives. This chemical approach allows control of film properties through solution chemistry rather than physical process parameters, simplifying the overall process while maintaining film stability
2Reliability
If vacuum processes are used to form oxide semiconductor films, then films can be produced, but oxygen vacancies cannot be effectively reduced leading to film instability
Solution Approach 1:
The patent uses oxygen plasma treatment or annealing in an oxygen atmosphere as a strong oxidation step after film formation. This accelerates the oxidation of metal species and fills oxygen vacancies in the oxide semiconductor film, significantly improving film stability and reducing harmful defects
Solution Approach 2:
The coating liquid is formulated as a composite material containing multiple metal organic compounds (e.g., In, Ga, Zn) along with specific additives. This composite approach allows synergistic effects during film formation and oxidation, enabling better control of oxygen vacancy formation and film stability
3Ease of manufacture
If liquid phase methods are used to form oxide semiconductor films, then process cost is reduced and simplicity is improved, but film properties remain insufficient
Solution Approach 1:
The patent optimizes multiple parameters of the liquid-phase process including solvent selection, metal organic compound ratios, coating thickness, and heating temperature profiles. These parameter optimizations enable the simple liquid-phase process to produce films with properties comparable to or better than vacuum processes
Solution Approach 2:
The introduction of oxygen plasma treatment or oxygen annealing as a post-coating step provides strong oxidation that completes the film formation process. This additional oxidation step ensures high-quality oxide semiconductor films are formed through the simple liquid-phase approach, achieving desired electrical properties
4Manufacturing precision
If vacuum processes are used, then films can be formed, but trace element uniformity cannot be achieved
Solution Approach 1:
The patent replaces physical vapor deposition with liquid-phase coating, where trace elements are introduced as metal organic compounds in solution. The liquid phase ensures homogeneous distribution of trace elements at the molecular level before film formation, achieving superior uniformity that is difficult to obtain through vacuum processes
Solution Approach 2:
The coating liquid is designed with homogeneous distribution of all metal species including trace elements. The solution chemistry ensures that metal organic compounds are uniformly dispersed throughout the liquid phase, leading to uniform incorporation into the film during the coating and heating process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables the production of uniform, stable n-type oxide semiconductor films with desired properties, overcoming the limitations of existing vacuum processes by allowing for precise control of film formation and reducing oxygen vacancies, resulting in high-performance TFTs.
Implementation Method 1
capable of forming a large area of an n-type oxide semiconductor film having a desired volume resistivity at a low process temperature
Implementation Method 2
formation of stable n-type oxide semiconductor films with controlled volume resistivity and carrier density at low temperatures
Data Source
AI summary
A coating liquid for forming an n-type oxide semiconductor film, the coating liquid including: a Group A element, which is at least one selected from the group consisting of Sc, Y, Ln, B, Al, and Ga; a Group B element, which is at least one of In and Tl; a Group C element, which is at least one selected from the group consisting of Group 4 elements, Group 5 elements, Group 6 elements, Group 7 elements, Group 8 elements, Group 9 elements, Group 10 elements, Group 14 elements, Group 15 elements, and Group 16 elements; and a solvent.