ISZO Oxide Semiconductor Composition for High-Mobility TFTs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing oxide semiconductor thin film transistors, particularly those with an indium gallium zinc oxide (IGZO) composition, face significant lattice mismatch issues at low temperatures, leading to defects and low mobility, which hinder the achievement of high-definition displays and improved driving performance.
Innovation Solution
An oxide semiconductor composition comprising indium oxide, zinc oxide, and scandium oxide, with a molar ratio of scandium oxide to zinc oxide approximately 1:1 and a high molar percentage of indium oxide, is developed, along with a manufacturing method involving powder mixing and sintering at high temperatures to reduce oxygen vacancies and enhance mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If indium gallium zinc oxide (IGZO) composition is used in oxide semiconductor TFT, then the crystal lattice stability is improved, but the mobility is reduced due to serious lattice mismatch at low temperature
Solution Approach 1:
The patent changes the compositional parameters by replacing Ga3+ with Sc3+ in the IGZO system, creating ISZO composition. This parameter change resolves the lattice mismatch issue at low temperature while maintaining crystal lattice stability, thereby improving carrier mobility without sacrificing structural stability.
Solution Approach 2:
The patent creates a composite oxide semiconductor material ISZO by combining indium oxide, scandium oxide, and zinc oxide in specific ratios. This composite material integrates the advantages of different oxides: In2O3 provides high carrier mobility, ZnO provides structural stability, and Sc2O3 suppresses oxygen vacancies, achieving both stability and high mobility simultaneously.
2Ease of manufacture
If low temperature processing is used to avoid lattice mismatch, then manufacturing complexity is reduced, but oxygen vacancies increase leading to low mobility
Solution Approach 1:
The patent introduces Sc3+ as an intermediary element that mediates between the conflicting requirements of low temperature processing and high mobility. Sc3+ has appropriate ionic radius and oxygen-binding capacity to stabilize the crystal lattice at low processing temperatures while suppressing oxygen vacancies, enabling low temperature manufacturing without sacrificing mobility performance.
Solution Approach 2:
The patent changes the chemical composition parameters by incorporating Sc2O3 into the oxide semiconductor system. This composition modification allows the material to maintain high mobility even at low processing temperatures by suppressing oxygen vacancies through Sc3+'s strong oxygen-binding capacity, thus resolving the contradiction between ease of manufacture and reliability.
3Speed
If scandium oxide is added to suppress oxygen vacancies, then mobility is improved, but manufacturing precision requirements increase due to specific molar ratios
Solution Approach 1:
The patent optimizes the compositional parameters by determining specific molar ratios of In2O3:Sc2O3:ZnO (7:1.5:1.5 or 7:2:2). These optimized parameters balance the mobility enhancement from Sc3+ with the manufacturing precision requirements, making the composition robust and easier to manufacture while maintaining high mobility performance.
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 composition and method result in reduced oxygen vacancies and defects, significantly improving the mobility of the oxide semiconductor, enabling higher-resolution displays and enhanced driving performance by ensuring a high purity and improved film quality.
Implementation Method 1
sintering the oxide shaped object to form the oxide semiconductor composition
Implementation Method 2
sintering at high temperatures to reduce oxygen vacancies and enhance mobility
Data Source
AI summary
An oxide semiconductor composition for use in thin film transistors includes indium oxide, zinc oxide, and an oxide including a doping element of scandium, such as scandium oxide. A molar percentage of the indium oxide can be larger than approximately 50%. The oxide semiconductor composition can have a formula of In2Sc2ZnO7. Manufacturing of the oxide semiconductor composition can include: mixing indium oxide powder, scandium oxide powder, and zinc oxide powder to thereby obtain an oxide shaped object; and sintering the oxide shaped object to form the oxide semiconductor composition. A thin-film transistor for use in a semiconductor device, such as a display apparatus, can include the oxide semiconductor composition, and can thereby have improved mobility of the oxide semiconductor due to the reduced oxygen vacancy therein.