Zirconium-Doped Zinc Oxide Monolayer Deposition for Step Coverage
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Solution Overview
Problem
Current methods for forming zirconium-doped zinc oxide (ZZO) films, such as sputtering and laser deposition, do not produce structures with the necessary quality and cost-effectiveness for advanced electronic devices, lacking in transparency, resistivity, crystallinity, and mechanical properties.
Innovation Solution
The use of monolayer deposition techniques, specifically atomic layer deposition (ALD) and reaction sequence ALD (RS-ALD), to form ZZO films with precise control over layer thickness and composition, achieving conformal coverage over complex topographies and enabling amorphous or nanocrystalline structures with improved durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sputtering or laser deposition methods are used to form ZZO films, then the materials can be deposited, but the resulting films lack sufficient quality in terms of transparency, resistivity, crystallinity, and mechanical properties
Solution Approach 1:
The deposition process is segmented into multiple sequential ALD cycles, where zinc oxide and zirconium oxide layers are deposited alternately in monolayer precision. This segmentation allows independent optimization of each layer's properties and achieves superior overall film quality that cannot be obtained through conventional sputtering or laser deposition methods.
Solution Approach 2:
The patent employs precise control of deposition parameters including temperature, pressure, and precursor flow rates during ALD processing. By optimizing these parameters, the method achieves enhanced transparency, resistivity, and crystallinity in the ZZO films, resolving the quality issue while maintaining manufacturability through automated process control.
2Manufacturing precision
If conventional deposition methods are used, then the manufacturing process is simpler, but the step coverage and conformal coverage over complex topographies are insufficient
Solution Approach 1:
The film deposition is divided into sequential monolayer cycles that sequentially build up the film conformally over complex topographies. Each ALD cycle deposits a uniform monolayer that conforms to the underlying structure, achieving excellent step coverage that is impossible with line-of-sight methods like sputtering or laser deposition.
Solution Approach 2:
The ALD process uses intermediary chemical reactions between precursors and the substrate surface to achieve conformal deposition. The sequential surface reactions enable precise control over film formation, allowing complete coverage of complex three-dimensional structures with uniform thickness and composition.
3Reliability
If ITO is used instead of ZZO, then high transparency and low resistivity are achieved, but chemical stability at higher temperatures is limited
Solution Approach 1:
The patent creates a composite transparent conducting oxide by combining zinc oxide and zirconium oxide in specific ratios through ALD deposition. This composite material achieves superior high-temperature chemical stability compared to ITO while maintaining the desired electrical and optical properties, and uses abundant, non-toxic materials that are more cost-effective than indium-based ITO.
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
Results in ZZO films with enhanced transparency, resistivity, and mechanical properties, suitable for advanced electronic devices, offering superior step coverage and durability compared to conventional methods.
Implementation Method 1
depositing a first monolayer that includes zinc and a second monolayer that includes zirconium
Data Source
AI summary
Methods of forming transparent conducting oxides and devices formed by these methods are shown. Monolayers that contain zinc and monolayers that contain zirconium are deposited onto a substrate and subsequently processed to form zirconium-doped zinc oxide. The resulting transparent conducing oxide includes properties such as an amorphous or nanocrystalline microstructure. Devices that include transparent conducing oxides formed with these methods have better step coverage over substrate topography and more robust film mechanical properties.