Thin Film Transistor Gate Insulating Layer Oxidation
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Solution Overview
Problem
Conventional thin film transistor (TFT) devices have unsatisfactory insulating properties due to the use of low-quality gate insulating layers with low dielectric constants, leading to increased leakage current and operating voltage, and extended process times.
Innovation Solution
A method for manufacturing a TFT with a dense gate insulating layer formed by oxidizing a portion of the semiconductor layer, creating a first gate insulating layer in direct contact with the active layer, and optionally combining it with a second insulating layer, resulting in a dielectric intensity of at least 8×10^6 V·cm−1, using techniques like thermal oxidation and excimer laser annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gate insulating layer is formed using conventional CVD or sputtering processes at low formation temperature, then the process time is reduced and manufacturing is easier, but the gate insulating layer has a loose texture and unsatisfactory insulating property with dielectric intensity of only approximately 5.6×10^6 V·cm−1
Solution Approach 1:
The patent changes the formation temperature parameter from low temperature (conventional CVD/sputtering) to high temperature (900-1100°C thermal oxidation) to transform the texture from loose to dense, achieving dielectric intensity of at least 8×10^6 V·cm−1. This parameter change fundamentally improves the insulating property while maintaining process simplicity through a single thermal oxidation step.
Solution Approach 2:
The patent replaces the mechanical deposition processes (CVD, sputtering) with a chemical oxidation process. Instead of physically depositing material, the gate insulating layer is formed in-situ by oxidizing the semiconductor layer through thermal diffusion, eliminating the need for separate deposition equipment and processes while achieving superior density and insulating properties.
2Reliability
If the gate insulating layer is thickened to improve insulating property, then the dielectric intensity increases, but the operating voltage of the device increases and the process time is extended
Solution Approach 1:
The patent changes the temperature parameter to high temperature (900-1100°C) thermal oxidation, which dramatically increases the oxidation rate. This allows formation of a dense gate insulating layer with dielectric intensity of at least 8×10^6 V·cm−1 in a short time (5-30 minutes), avoiding the need for thickening the layer to improve insulating property, thus maintaining low operating voltage and short process time.
3Temperature
If the gate insulating layer is formed by conventional low temperature processes, then the process temperature is reduced and manufacturing is easier, but the formed gate insulating thin layer has a relatively loose texture and unsatisfactory insulating property
Solution Approach 1:
Instead of forming the gate insulating layer by deposition at low temperature and then hoping for good properties, the patent inverts the approach by forming it through high-temperature oxidation of the semiconductor layer itself. The semiconductor layer serves as the source of the gate insulating material, and the high temperature ensures dense texture and superior insulating property (dielectric intensity of at least 8×10^6 V·cm−1) is achieved inherently through the oxidation 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 method improves the electrical properties of TFTs by reducing leakage current and process time, while ensuring a high-quality interface between the active layer and gate insulating layer, enhancing device performance.
Implementation Method 1
the first gate insulating layer being formed by oxidizing a portion of the semiconductor layer
Implementation Method 2
using techniques like thermal oxidation and excimer laser annealing
Implementation Method 3
using techniques like thermal oxidation and excimer laser annealing
Data Source
AI summary
Embodiments of the present invention provide a thin film transistor, a manufacturing method thereof and a display device. The method for manufacturing the thin film transistor, comprising the following steps: providing a substrate; forming a semiconductor layer on the substrate; forming a gate insulating layer; and forming a gate electrode, wherein the gate insulating layer comprises a first gate insulating layer, the first gate insulating layer being formed by oxidizing a portion of the semiconductor layer, and the unoxidized portion of the semiconductor layer forming an active layer, and wherein the gate electrode is formed in such a way that the gate insulating layer is sandwiched between the gate electrode and the active layer.