Thin Film Transistor Channel Segmentation for Enhanced S-Factor
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Solution Overview
Problem
Thin film transistors typically have small s-factors, making it difficult to express gray scales effectively in display apparatus, and they often lack improved current characteristics in the ON state.
Innovation Solution
A thin film transistor design featuring a channel portion driven by a fringing electrical field, with a gate electrode partially overlapping an active layer composed of a first and second active layer, where the second active layer has higher mobility and is configured to receive a fringing electric field, while the first active layer is primarily affected by a uniform electric field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thin film transistor is designed with conventional channel structure, then manufacturing is simple, but s-factor is small and gray scale expression is difficult
Solution Approach 1:
The channel portion is divided into two distinct regions: a first channel part under the gate electrode and a second channel part outside the gate electrode. This segmentation allows each region to be controlled by different electric field mechanisms, enabling independent optimization of s-factor and current characteristics without complicating the overall manufacturing process
Solution Approach 2:
The invention extends the channel region into a second dimension by creating a second channel part that exists outside the gate electrode's projection area. This dimensional extension allows the channel to be controlled not only by the direct electric field under the gate but also by fringing electric fields, thereby improving s-factor without increasing manufacturing complexity
2Manufacturing precision
If thin film transistor uses single active layer, then structure is simple, but current characteristics in ON state are insufficient
Solution Approach 1:
The active layer is designed with different materials in different regions: the first active layer has lower mobility and is affected by uniform electric field, while the second active layer has higher mobility and is affected by fringing electric field. This local differentiation optimizes current characteristics in the ON state by utilizing the high-mobility region when the transistor is activated
Solution Approach 2:
The active layer comprises a composite structure of two different semiconductor materials with distinct mobility characteristics. This composite design allows the transistor to leverage both materials' properties: the lower-mobility material provides stable threshold voltage control while the higher-mobility material enhances on-state current, achieving superior current characteristics without excessive structural complexity
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 design enhances the s-factor and on-current characteristics, enabling better gray scale expression and current handling in display devices.
Implementation Method 1
a part of a channel portion is designed to be driven by a fringing electrical field generated in a gate electrode
Data Source
AI summary
A thin film transistor, a manufacturing method of the thin film transistor and display apparatus including the thin film transistor are provided. The thin film transistor comprises an active layer and a gate electrode that partially overlaps the active layer, wherein the active layer includes a channel portion, a first connection portion contacting one side, namely a first side, of the channel portion and a second connection portion spaced apart from the first connection portion and contacting the other side, namely a second side of the channel portion, wherein the channel portion includes a first channel part overlapping the gate electrode and a second channel part not overlapping the gate electrode.