Conductive Laminated Body With Metal Oxide Interlayer
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Solution Overview
Problem
Conventional transparent conductive films, particularly those using zinc oxide, face challenges in achieving low resistivity due to the inverse relationship between electron concentration and mobility, leading to uneven resistivity and reduced heat/moisture resistance, especially when deposited using sputtering methods.
Innovation Solution
Incorporating a metal oxide interlayer with an oxidation number of +3, such as Al2O3 or Ga2O3, between the substrate and the zinc oxide-based thin film to increase electron concentration without reducing mobility, thereby improving resistivity and achieving uniform electrical properties across the film surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the concentration of electrons is increased by increasing the amount of dopant in the sputtering target, then the resistivity decreases, but the mobility is decreased due to collision between electrons and dopant acting as scattering centers
Solution Approach 1:
An aluminum oxide interlayer is introduced between the substrate and the zinc oxide-based thin film to act as an intermediary. This interlayer modifies the interface properties and electron transport characteristics, enabling high electron concentration while maintaining electron mobility by reducing scattering effects at the substrate interface.
2Productivity
If high power sputtering is used to increase deposition rate, then productivity increases, but the deposited film is damaged by high energy particles causing unevenness of resistivity
Solution Approach 1:
The aluminum oxide interlayer is formed in advance before depositing the zinc oxide-based thin film. This preliminary action prepares a protective and structurally sound interface that can withstand high-energy particle bombardment during high-power sputtering, preventing film damage and ensuring uniform resistivity even at high deposition rates.
3Ease of manufacture
If zinc oxide-based material is used as a substitute for ITO, then cost is reduced and harmlessness is improved, but electrical conductivity is lower than ITO
Solution Approach 1:
The aluminum oxide interlayer changes the physical and chemical parameters at the substrate-film interface, including electron scattering rates and film stress distribution. This parameter modification enables zinc oxide-based films to achieve electrical conductivity comparable to ITO while maintaining the advantages of lower cost and environmental safety.
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 interlayer effectively decreases film defects, maintains electron mobility, and ensures uniform resistivity and heat/moisture resistance, even with varying substrate types and deposition conditions, enhancing the film's applicability in diverse fields.
Implementation Method 1
the interposition of an interlayer including a metal oxide having an oxidation number +3, between the substrate and the zinc oxide-based thin film, can increase the concentration of electrons without a reduction of electron mobility
Implementation Method 2
resistivity of a transparent conductive film having a certain thickness is in inverse proportion to concentration of electrons and mobility (ρ=1/(eμN))
Implementation Method 3
a vacuum-deposition method, such as sputtering
Implementation Method 4
the interposition of an interlayer including a metal oxide having an oxidation number +3, between the substrate and the zinc oxide-based thin film, can increase the concentration of electrons without a reduction of electron mobility, and can improve the resistivity property by removing defects being caused by high energy particles in sputtering
Data Source
AI summary
Disclosed is a conductive laminated body, and a method for preparing the same, wherein the conductive laminated body including: a substrate; a zinc oxide-based thin film doped with an element M; and an interlayer including an oxide M′2O3, which is interposed between the substrate and the zinc oxide-based thin film. The disclosed conductive laminated body includes a metal oxide interlayer of an oxidation number +3, between a substrate and a zinc oxide layer. Therefore, it is possible to improve electrical properties of a transparent conductive thin film, especially, a resistivity property, and to minimize the unevenness in electrical properties between a middle portion and a circumferential portion on the surface of the thin film in sputtering deposition. Also, in deposition of a zinc oxide film, in addition to inert gas such as argon gas, the use of hydrogen gas can improve the concentration of electrons, and herein, the interposition of an interlayer including a metal oxide, between the substrate and the zinc oxide-based transparent conductive film, allows the heat-resistance/moisture-resistance stability and the uniformity of electrical properties.