IGZO Transparent Conductor Thin Films via Atomic-Layer Digital Doping
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Solution Overview
Problem
There is a need for new and improved transparent conductor oxide (TCO) materials and methods for fabricating TCOs, as existing materials like indium tin oxide (ITO) are expensive and have limitations in conductivity and transparency.
Innovation Solution
A thin film comprising multiple oxide layers with single atomic layers of dopant materials, such as Ga2O3 and In2O3, deposited using atomic layer deposition (ALD) to create a doped oxide semiconductor material like indium gallium doped zinc oxide (IGZO), which achieves high conductivity and transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional TCO materials like ITO are used, then transparency is achieved, but cost increases and conductivity is limited
Solution Approach 1:
The patent uses composite materials by combining multiple oxide layers (ZnO, Ga2O3, In2O3) with single atomic layer dopants to create IGZO thin films that achieve superior conductivity and transparency compared to conventional ITO, while reducing material cost through optimized composition and thickness control
Solution Approach 2:
The patent applies parameter changes by precisely controlling the thickness of each oxide layer and dopant concentration at the atomic layer level, achieving optimal balance between conductivity, transparency, and cost without requiring expensive post-deposition processing
2Reliability
If doping concentration is increased to improve conductivity, then electrical performance improves, but transparency deteriorates
Solution Approach 1:
The patent applies local quality by introducing dopant atoms at specific atomic layer positions within the oxide structure, creating localized doping regions that enhance conductivity without uniformly increasing free carrier concentration throughout the entire film thickness, thereby maintaining optical transparency
Solution Approach 2:
The patent uses parameter changes by precisely controlling dopant concentration at the atomic layer level and optimizing the thickness of each oxide layer to achieve the optimal balance between electrical conductivity and optical transparency, avoiding the trade-off present in conventional bulk doping approaches
3Reliability
If complex doping processes are used to achieve high conductivity, then electrical performance improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by incorporating dopant atoms directly during the atomic layer deposition process itself, rather than requiring subsequent separate doping steps or post-deposition annealing treatments, thereby simplifying the overall manufacturing process while achieving high conductivity
Solution Approach 2:
The patent uses self-service by designing a doping process that occurs intrinsically during the standard ALD deposition sequence, where the dopant layers are automatically integrated into the oxide structure during growth, eliminating the need for additional dedicated doping equipment or complex process steps
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 resulting IGZO thin films exhibit high conductivity, transparency, and stability, comparable or superior to industry standards, with a band gap of 3.4 eV, mobility greater than 10 cm2/V×s, and n-type carrier density of 1019 cm−3, making them suitable for optoelectronic devices without the need for post-deposition annealing.
Implementation Method 1
single atomic layers of dopant materials, such as Ga2O3 and In2O3, deposited using atomic layer deposition (ALD)
Data Source
AI summary
Compositions, thin films, devices, and methods involving doped oxide semiconductor materials are described. Indium gallium doped zinc oxide (IGZO) with advantageous properties that may be useful as a transparent conductive oxide (TCO) is described. Methods of digital doping to create doped oxide semiconductor materials are described.