LTPS TFT Modulation Electrode Leakage Current
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Solution Overview
Problem
The leakage current in Low Temperature Poly Silicon-Thin Film Transistors (LTPS-TFTs) is a significant issue affecting their quality due to the tunneling effect caused by excessive energy band bending at high electric field intensities.
Innovation Solution
The introduction of a modulation electrode proximate to the drain, which generates an opposite electric field when the thin film transistor is turned off, alleviates the energy band bending and reduces leakage current by applying opposite signal levels to the gate and modulation electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional LTPS-TFT structure is used, then high electron mobility is achieved, but leakage current increases due to excessive energy band bending at high electric field intensities
Solution Approach 1:
The gate electrode is divided into two independent parts: a conventional gate and a modulation electrode. This segmentation allows independent control of the channel and the drain junction, enabling the modulation electrode to specifically address the leakage current issue by controlling the energy band bending at the drain region without affecting the overall high electron mobility characteristic of the LTPS-TFT structure.
2Reliability
If the gate voltage is increased to control the transistor, then the transistor turns off, but excessive energy band bending occurs causing charge tunneling and leakage current
Solution Approach 1:
The modulation electrode applies a preliminary counteracting electric field to offset the excessive energy band bending caused by the gate voltage. When the gate voltage creates strong field effect that leads to harmful energy band bending at the drain, the modulation electrode simultaneously applies an opposite polarity voltage to create a counteracting field that prevents the energy bands from bending excessively, thereby suppressing charge tunneling and leakage current before they can occur.
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 configuration effectively reduces leakage current and stabilizes the circuit by preventing charge tunneling, thereby improving the overall performance of the thin film transistor.
Implementation Method 1
the modulation electrode is proximate to the drain, and an orthographic projection of the modulation electrode on the base substrate has an overlap area with an orthographic projection of the semiconductor active layer on the base substrate
Data Source
AI summary
This disclosure relates to the field of display technologies, and discloses a thin film transistor, a method for fabricating the same, a method for controlling the same, a display panel, and a display device. The thin film transistor includes: a base substrate, a semiconductor active layer on one side of the base substrate, a source electrically connected with one end of the semiconductor active layer, a drain electrically connected with the other end of the semiconductor active layer, a gate insulated from the semiconductor active layer, the source, and the drain, and a modulation electrode insulated from the semiconductor active layer, the gate, the source, and the drain. The modulation electrode is proximate to the drain, and an orthographic projection of the modulation electrode on the base substrate overlaps with an orthographic projection of the semiconductor active layer on the base substrate