PZT Film Structure With Oriented Buffer Layers for Better Crystallinity
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Solution Overview
Problem
The piezoelectric properties of lead zirconate titanate films deteriorate due to unfavorable crystallinity, making it difficult to form high-quality films with improved properties.
Innovation Solution
A film structure is developed with a silicon substrate, a (100)-oriented zirconium oxide film, a platinum film, and a lead zirconate titanate film, where the interface roughness between the zirconium oxide and platinum films is greater than between the substrate and zirconium oxide, and the lead zirconate titanate film is tetragonally oriented with a specific lattice constant ratio, enhancing crystallinity and piezoelectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a lead zirconate titanate piezoelectric film is formed on a conventional substrate, then the film can be manufactured, but the crystallinity and piezoelectric properties deteriorate due to unfavorable interface quality
Solution Approach 1:
The patent introduces a zirconium oxide film as an intermediary layer between the silicon substrate and the lead zirconate titanate piezoelectric film. This intermediary layer with specific (100) orientation serves as a buffer that improves the interface quality and lattice matching, enabling the formation of high-quality c-axis oriented PZT films with excellent crystallinity and piezoelectric properties
Solution Approach 2:
The patent controls the crystal orientation parameter of the zirconium oxide film to be (100)-oriented, which is a critical parameter change from conventional approaches. This specific orientation parameter enables optimal lattice matching with both the silicon substrate and the PZT film, thereby improving crystallinity and piezoelectric properties
2Manufacturing precision
If the interface roughness between zirconium oxide and platinum is increased, then the piezoelectric film quality improves, but the manufacturing process becomes more complex
Solution Approach 1:
The patent optimizes the interface roughness parameter between the zirconium oxide and platinum films to enhance piezoelectric film quality. By controlling the roughness within specific ranges, the patent achieves improved crystallinity and piezoelectric properties without requiring excessively complex manufacturing processes
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
This approach improves the piezoelectric properties and detection sensitivity of sensors by increasing the content of tetragonally oriented lead zirconate titanate, reducing the relative dielectric constant, and enhancing the ferroelectric properties of the film.
Implementation Method 1
a first film that is formed on the main surface and includes a first zirconium oxide film which has a cubic crystal structure and is (100)-oriented
Implementation Method 2
a conductive film that is formed on the first film and includes a platinum film which has a cubic crystal structure and is (100)-oriented
Implementation Method 3
a piezoelectric film which contains lead zirconate titanate and is formed on the conductive film
Data Source
AI summary
A film structure includes a substrate (11) which is a silicon substrate including an upper surface (11a) composed of a (100) plane, an alignment film (12) which is formed on the upper surface (11a) and includes a zirconium oxide film which has a cubic crystal structure and is (100)-oriented, and a conductive film (13) which is formed on the alignment film (12) and includes a platinum film which has a cubic crystal structure and is (100)-oriented. An average interface roughness of an interface (IF1) between the alignment film (12) and the conductive film (13) is greater than an average interface roughness of an interface (IF2) between the substrate (11) and the alignment film (12).