Gate-Body Contact TFT Edge Region Integration
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Solution Overview
Problem
Conventional gate-body contact thin film transistors (TFTs) have a larger area due to a separately extended body contact region, which degrades semiconductor layer characteristics and increases power consumption in display devices.
Innovation Solution
A gate-body contact TFT structure is developed without a separately extended body contact region, utilizing the edge region of the semiconductor layer as the body contact region, with a method that includes forming a semiconductor layer, a gate insulating layer, a silicon layer, and a gate electrode, and integrating it into an OLED display device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separately extended body contact region is formed in the semiconductor layer to achieve gate-body contact, then the subthreshold slope is improved and high drain current is obtained at low gate voltage, but the area of the semiconductor layer increases
Solution Approach 1:
The invention merges the body contact region with the edge region of the semiconductor layer by forming the gate insulating layer to expose the edge region, thereby achieving gate-body contact without a separately extended body contact region. This integration eliminates the need for additional area while maintaining the improved subthreshold slope and on/off characteristics.
Solution Approach 2:
The edge region of the semiconductor layer serves dual functions: as the channel region boundary and as the body contact region. By making the edge region serve multiple purposes, the invention achieves gate-body contact functionality without requiring additional dedicated area, thus resolving the contradiction between reliability improvement and area increase.
2Reliability
If the semiconductor layer area is increased to accommodate a separately extended body contact region, then gate-body contact is achieved, but power consumption increases in display devices
Solution Approach 1:
The invention combines the body contact function with the existing edge region of the semiconductor layer, eliminating the need for an extended body contact region. This merger reduces the overall semiconductor layer area, which directly lowers power consumption in display devices while maintaining the improved on/off characteristics through gate-body contact.
3Manufacturing precision
If photoresist pattern is formed and etching is performed to define the semiconductor layer, then the semiconductor layer structure is defined, but the edge region is damaged by etch solution or plasma
Solution Approach 1:
The invention converts the potentially harmful edge region, which is vulnerable to etching damage, into a beneficial body contact region. By exposing the edge region through selective gate insulating layer formation and using it as the body contact area, the invention transforms the weakness into a functional advantage, achieving gate-body contact while accepting the etched edge as the contact interface.
Data Source
AI summary
A thin film transistor, a method of fabricating the same, and an OLED display device having the same. The thin film transistor includes a substrate, a semiconductor layer disposed on the substrate and having a channel region, source and drain regions, and a body contact region, a gate insulating layer disposed on the semiconductor layer to expose the body contact region, a silicon layer disposed on the gate insulating layer and contacting the body contact region exposed by the gate insulating layer, a gate electrode disposed on the silicon layer, an interlayer insulating layer disposed on the gate electrode, and source and drain electrodes disposed on the interlayer insulating layer and electrically connected with the source and drain regions, wherein the body contact region is formed in an edge region of the semiconductor layer.