Oxide Semiconductor TFT Oxygen Supply and Anti-Diffusion Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Oxide semiconductor TFTs face defects and reliability issues due to oxygen deficiencies and damage during manufacturing, particularly during heat treatment and etching processes, which affect the electrical characteristics and pixel density in liquid crystal display devices.
Innovation Solution
A semiconductor device configuration with a gate electrode, oxide semiconductor layer, source and drain electrodes, a protective layer, an oxygen supplying layer, and an anti-diffusion layer, where the transparent electrode is made of amorphous transparent oxide, and the anti-diffusion layer can be crystalline transparent oxide, to prevent hydrogen diffusion and oxygen deficiencies, enhancing the reliability and pixel density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If oxide semiconductor TFT is used to increase operating speed, then higher mobility is achieved, but oxygen deficiencies occur during manufacturing causing threshold voltage shift
Solution Approach 1:
The patent applies preliminary action by forming the oxide semiconductor layer with controlled oxygen content before subsequent manufacturing steps. The layer is prepared in advance with sufficient oxygen to prevent deficiencies during heat treatment and etching processes, thereby maintaining electrical characteristic stability while achieving high operating speed
Solution Approach 2:
The patent changes the oxygen content parameter of the oxide semiconductor layer to optimize performance. By controlling the oxygen concentration within specific ranges (5-20 at% excess oxygen), the invention achieves both high carrier mobility for fast operation and stability of threshold voltage by preventing oxygen deficiency during manufacturing
2Ease of manufacture
If heat treatment process is applied to manufacture TFT, then manufacturing is completed, but oxygen deficiencies are caused in oxide semiconductor layer
Solution Approach 1:
The patent applies beforehand cushioning by incorporating an oxygen-containing layer adjacent to the oxide semiconductor layer before heat treatment. This layer serves as an oxygen reservoir that compensates for oxygen loss during heat treatment and etching processes, maintaining manufacturing precision while enabling complete manufacturing
Solution Approach 2:
The patent controls the oxygen content parameter of the oxide semiconductor layer to be within 5-20 at% excess oxygen, and adjusts the oxygen content in the adjacent layer to 10-30 at%. These parameter changes enable the material to withstand heat treatment without significant oxygen loss, achieving both manufacturing completion and precision
3Ease of manufacture
If etching process is applied to form source and drain electrodes, then electrode formation is completed, but underlying oxide semiconductor layer is damaged by reduction action
Solution Approach 1:
The patent introduces an oxygen-containing layer as an intermediary between the oxide semiconductor layer and the etching process. This intermediary layer protects the oxide semiconductor layer from reduction damage during etching by providing oxygen that prevents reduction reactions, while still allowing the etching process to complete electrode formation
Solution Approach 2:
The patent adjusts the oxygen content parameter of the oxide semiconductor layer to 5-20 at% excess oxygen, which creates a buffer against reduction during etching. This parameter change maintains the integrity of the oxide semiconductor layer while enabling complete electrode formation
4Illumination intensity
If transparent electrode is formed to increase aperture ratio, then transmittance is improved, but hydrogen diffusion occurs affecting TFT characteristics
Solution Approach 1:
The patent introduces a barrier layer as an intermediary between the transparent electrode and the oxide semiconductor layer. This barrier layer prevents hydrogen diffusion from the transparent electrode into the oxide semiconductor layer, maintaining TFT electrical characteristic stability while allowing the transparent electrode to provide high transmittance
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 configuration reduces defects in the oxide semiconductor layer, improves the electrical characteristics, and increases the number of pixels effectively by preventing oxygen deficiencies and hydrogen diffusion, leading to enhanced reliability and display quality.
Implementation Method 1
an oxygen supplying layer formed on the protective layer
Implementation Method 2
an anti-diffusion layer formed on the oxygen supplying layer
Data Source
AI summary
A semiconductor device (100a) with a thin-film transistor (10a) includes: a gate electrode (62) formed on a substrate (60); a gate insulating layer (66) formed on the gate electrode; an oxide semiconductor layer (68) formed on the gate insulating layer; source and drain electrodes (70s, 70d) electrically connected to the oxide semiconductor layer; a protective layer (72) formed on the oxide semiconductor layer and the source and drain electrodes; an oxygen supplying layer (74) formed on the protective layer; an anti-diffusion layer (78) formed on the oxygen supplying layer; and a transparent electrode (81) formed on the anti-diffusion layer and made of an amorphous transparent oxide.