In-Hf-Ta-O Sputtering Target for Low-Temperature Transparent Conductive Films
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Solution Overview
Problem
Existing transparent conductive oxide films, such as ITO, face challenges in simultaneously optimizing electrical resistance and optical transmittance, especially when used with organic substrates or at low temperatures, where current methods fail to achieve low resistance at temperatures below 150°C without compromising film quality.
Innovation Solution
An oxide sintered body composed of indium, hafnium, and tantalum with specific atomic ratios and a high relative density, used as a sputtering target to produce a transparent conductive oxide film, which allows for low resistance and high transmittance even at low processing temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of SnO2 is increased to reduce resistance, then electrical characteristics improve, but the plasma wavelength shifts to shorter wavelengths causing decreased transmittance in the infrared region
Solution Approach 1:
The invention changes the compositional parameters by introducing hafnium oxide and tantalum oxide as alternative dopants to SnO2. By adjusting the atomic ratios of Hf and Ta relative to In within specific ranges (Hf: 0.2-3.0 at%, Ta: 0.02-1.3 at%), the patent achieves optimal balance between resistance and transmittance without the adverse plasma wavelength shift caused by excessive SnO2
Solution Approach 2:
The invention creates a composite oxide sintered body combining indium oxide with hafnium oxide and tantalum oxide. This multi-component composite material (In-Hf-Ta-O system) leverages the complementary properties of each oxide to achieve both low resistance and high transmittance, resolving the trade-off between electrical and optical characteristics
2Reliability
If conventional sputtering processes are used to achieve low resistance, then electrical characteristics improve, but the process temperature becomes too high for organic substrates and polymer films
Solution Approach 1:
The invention changes the material composition parameters by incorporating hafnium oxide and tantalum oxide, which enable low-temperature sputtering processing. The specific atomic ratio ranges of Hf (0.2-3.0 at%) and Ta (0.02-1.3 at%) in the In-Hf-Ta-O system facilitate film formation at 150°C or lower while maintaining low resistivity, making the process compatible with temperature-sensitive substrates
3Illumination intensity
If high transmittance is prioritized by reducing metal content, then optical characteristics improve, but resistance increases
Solution Approach 1:
The invention optimizes the compositional parameters by precisely controlling the atomic ratios of Hf and Ta dopants within specific ranges. This parameter optimization enables achieving both high transmittance and low resistance simultaneously, as the controlled doping level maintains optical transparency while providing sufficient charge carriers for low resistivity
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 transparent conductive oxide film achieves low resistivity of 300 µΩ·cm or lower at temperatures as low as 150°C, facilitating electronic device production and ensuring durability in high-temperature or high-humidity environments.
Implementation Method 1
a method for producing a transparent conductive oxide film comprising sputtering using the oxide sintered body as a sputtering target
Data Source
AI summary
Provided are an oxide sintered body that can produce a transparent conductive oxide film having low resistance and exhibiting lower light absorption characteristics in a wide wavelength range, and a transparent conductive oxide film. An oxide sintered body containing indium, hafnium, tantalum, and oxygen as constituent elements, in which when indium, hafnium, and tantalum are designated as In, Hf, and Ta, respectively, the atomic ratio Hf/(In + Hf + Ta) is 0.2 at% to 3.0 at%, and the atomic ratio Ta/(In + Hf+ Ta) is 0.02 at% to 1.3 at%, is used.