Complex Oxide Sputtering Target for Low Resistivity and Absorptivity
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Solution Overview
Problem
Existing transparent conductive oxide films, such as ITO films, face challenges in simultaneously achieving low resistivity and low light absorptivity across a wide wavelength range, which is crucial for applications like liquid crystal displaying elements and solar cells.
Innovation Solution
A complex oxide sintered body composed of indium, zirconium, and yttrium with specific atomic ratios is used to produce a transparent conductive oxide film, which is then formed into a sputtering target for depositing the film, thereby achieving low resistivity and low light absorptivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of SnO2 is increased to reduce resistance, then resistivity is improved, but light absorptivity in the infrared region increases
Solution Approach 1:
The invention changes the compositional parameters by replacing part of the SnO2 with Ga2O3, specifically setting Ga at 0.1-5 at% and Sn at 1-20 at% based on total metal elements. This parameter optimization allows achieving resistivity of 0.01-10 Ω/□ while maintaining low light absorptivity, resolving the contradiction between electrical conductivity and optical transparency.
Solution Approach 2:
The invention creates a composite oxide material In2O3-Ga2O3-SnO2 that combines the benefits of different metal oxides. Indium oxide provides the base transparent conductive properties, gallium oxide modifies the band structure to reduce infrared absorption, and tin oxide contributes to electrical conductivity. This composite approach allows simultaneous optimization of both resistivity and light absorptivity that cannot be achieved with single-element additions.
2Reliability
If a single metal element is added to indium oxide, then one property (resistance or light absorption) is improved, but the other property deteriorates
Solution Approach 1:
The patent employs a ternary composite system In2O3-Ga2O3-SnO2 where each component plays a specific role. Indium oxide forms the transparent conductive matrix, gallium oxide (0.1-5 at%) modifies the electronic band structure to reduce infrared absorption, and tin oxide (1-20 at%) provides charge carriers for conductivity. This multi-element composite enables simultaneous optimization of both electrical and optical properties, overcoming the limitations of single-element doping.
Solution Approach 2:
The invention applies different elements at optimized local concentrations within the crystal structure. Gallium preferentially occupies specific lattice sites to modify band gaps, while tin provides localized charge carriers. This localized optimization of elemental distribution allows independent tuning of electrical conductivity and optical absorption 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 resulting transparent conductive oxide film exhibits suppressed abnormal discharge during sputtering and maintains low resistivity and light absorptivity across a wide wavelength range, enhancing the performance of solar cells by reducing optical loss and improving photoelectric conversion efficiency.
Implementation Method 1
a method for producing a transparent conductive oxide film, wherein sputtering is performed using the sputtering target
Data Source
Figure 1
AI summary
The present invention provides a complex oxide sintered body 10 wherein Zr/(In + Zr + Y) is 0.05 to 4.5 at% and Y/(In + Zr + Y) is 0.005 to 0.5 at% in an atomic ratio when indium, zirconium, and yttrium are designated by In, Zr, and Y, respectively. Moreover, the present invention provides a sputtering target including the complex oxide sintered body 10 and a transparent conductive oxide film obtained by sputtering the sputtering target.