In-Zn-Ti-O Thin-Film Transistor Mobility
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current thin-film transistors using In--Ga--Zn--O (IGZO) as an active layer face challenges in achieving mobility higher than 10 cm2/Vs, which is insufficient for high-resolution, low-power, and high-frame-rate displays, necessitating the development of materials with higher mobility.
Innovation Solution
A thin-film transistor with an active layer formed from an oxide semiconductor film containing indium, zinc, and titanium, where the atomic proportions of indium, zinc, and titanium are within specific ranges, enabling a mobility of not less than 15 cm2/Vs and an on/off current ratio of eight digits, and a sputtering target composed of a sintered body of these oxides is used to deposit the film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If IGZO (In-Ga-Zn-O) is used as the active layer material, then the transistor can be manufactured with existing processes, but the mobility is limited to below 10 cm2/Vs
Solution Approach 1:
The patent changes the compositional parameters of the oxide semiconductor by replacing gallium with titanium, creating an In-Zn-Ti-O system. This parameter change (compositional substitution) enables mobility to exceed 10 cm2/Vs while maintaining the oxide semiconductor structure and manufacturing compatibility
Solution Approach 2:
The patent creates a composite oxide semiconductor material combining indium, zinc, and titanium oxides with specific atomic ratios (In: 24-80 at.%, Zn: 16-70 at.%, Ti: 0.1-20 at.%). This composite material approach achieves high mobility through synergistic effects of multiple metal oxides while maintaining structural stability
2Speed
If the titanium content is increased to improve mobility, then the mobility increases, but the on/off current ratio may deteriorate
Solution Approach 1:
The patent optimizes the titanium content parameter within a specific range (0.1-20 at.%, preferably 0.5-10 at.%) to balance mobility enhancement with on/off current ratio maintenance. This controlled parameter adjustment prevents excessive titanium from causing harmful effects while achieving the desired mobility improvement
Solution Approach 2:
The patent applies local quality by distributing titanium atoms specifically within the oxide semiconductor lattice at controlled concentrations, rather than uniform mixing. This localized compositional control ensures titanium provides mobility enhancement without disrupting the overall material structure and electrical characteristics
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 solution achieves a mobility of not less than 15 cm2/Vs and an on/off current ratio of eight digits, surpassing the limitations of IGZO-based transistors, while maintaining a carrier concentration of not more than 1×10^18/cm3 for stable switching characteristics.
Implementation Method 1
a sputtering target used for depositing the oxide semiconductor film
Data Source
AI summary
A thin-film transistor according to an embodiment of the present invention includes: a gate electrode; an active layer formed of an oxide containing indium, zinc, and titanium; a gate insulating film formed between the gate electrode and the active layer; and a source electrode and a drain electrode that are electrically connected to the active layer. Atomic proportions of elements relative to the total quantity of indium, zinc, and titanium that constitute the oxide may be not less than 24 at. % and not more than 80 at. % for indium, not less than 16 at. % and not more than 70 at. % for zinc, and not less than 0.1 at. % and not more than 20 at. % for titanium.