Oxide Thin Film Transistor Low-Temperature Crystallization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The manufacturing of oxide thin film transistors is complicated and costly due to the need for an etch stop layer, which requires precise control and can be affected by oxygen, hydrogen, and water, and the high crystallizing temperature of crystalline oxide active layers can damage other film layers.
Innovation Solution
A method is developed to form a crystalline oxide active layer by using an inducing layer film, which lowers the crystallizing temperature, allowing the oxide active layer to be crystallized without high-temperature processing, simplifying the fabrication process and reducing the risk of damaging other layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an etch stop layer is added to protect the oxide active layer during etching, then the oxide active layer is protected from being affected by oxygen, hydrogen and water, but the manufacturing process becomes complicated, manufacturing cost increases, and production capacity and yield are reduced
Solution Approach 1:
The patent removes the etch stop layer from the transistor structure entirely. Instead of adding a protective layer, the invention uses a bottom gate structure where the gate electrode serves as the etch stop function, and the oxide active layer is patterned before etching, eliminating the need for a separate etch stop layer while maintaining protection of the active layer
Solution Approach 2:
The gate electrode in the bottom gate structure performs multiple functions: it serves as the control electrode for transistor operation and simultaneously acts as the etch stop layer during source and drain etching processes, eliminating the need for a separate etch stop layer
2Device complexity
If a crystalline oxide active layer is used to eliminate the need for an etch stop layer, then the manufacturing process is simplified, but the crystallizing temperature is very high and is very likely to affect other film layers
Solution Approach 1:
The patent changes the crystallization temperature parameter from very high temperature (conventional method) to low temperature (below annealing temperature of other film layers). This is achieved by using a bottom gate structure with specific material composition that enables low-temperature crystallization of the oxide active layer, thereby avoiding damage to other film layers
3Reliability
If the oxide active layer is made of metal oxide, then the thin film transistor exhibits high electron mobility, low threshold voltage and good uniformity, but the oxide active layer is poor in stability and prone to influence by oxygen, hydrogen and water in etching environment
Solution Approach 1:
The patent performs preliminary patterning of the oxide active layer before the etching process. By defining the active layer pattern in advance, the subsequent etching process only needs to etch the source and drain regions, reducing exposure of the oxide active layer to the etching environment and minimizing the need for additional protective measures
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
This method enables the crystallization of oxide active layers at lower temperatures, simplifying the fabrication process, reducing manufacturing costs, and improving the stability and yield of oxide thin film transistors.
Implementation Method 1
heating the substrate subjected to the above step, and crystallizing the oxide active layer film through inducement of the inducing layer film to form a crystalline oxide active layer
Data Source
AI summary
The present invention provides a thin film transistor, a fabricating method thereof, an array substrate and a display device. The fabricating method of the thin film transistor of the present invention comprises: forming an inducing layer film and an oxide active layer film in contact therewith on a substrate, the oxide active layer film being provided above or below the inducing layer film; and heating the substrate subjected to the above step, crystallizing the oxide active layer film through inducement of the inducing layer film to form a crystalline oxide active layer.