Ferroelectric Film Sputtering for High-Concentration Doping
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Solution Overview
Problem
Conventional methods for producing ferroelectric films, such as the sol-gel technique, face limitations in achieving high-concentration doping of B-site donor ions without sintering assistants or acceptor ions, leading to reduced thickness and performance due to Pb defects and decreased ferroelectric performance.
Innovation Solution
A non-thermal equilibrium process, specifically sputtering, is used to form PZT-based ferroelectric films with a columnar-grain structure, allowing high-concentration doping of B-site donor ions up to 40 mol% without sintering assistants or acceptor ions, resulting in enhanced ferroelectric performance and increased thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-concentration doping of B-site donor ions is attempted using conventional sol-gel technique, then doping concentration increases, but Pb defects occur and ferroelectric performance decreases
Solution Approach 1:
The patent changes the fundamental parameter of the manufacturing process from thermal equilibrium (sol-gel) to non-thermal equilibrium (sputtering). This parameter change enables high-concentration doping of B-site donor ions up to 40 mol% without forming Pb defects, thereby maintaining superior ferroelectric performance while achieving the desired doping concentration
2Quantity of substance
If sintering assistants or acceptor ions are added to enable high-concentration doping, then doping concentration increases, but device complexity and manufacturing complexity increase
Solution Approach 1:
The patent extracts and eliminates the need for sintering assistants (Si, Ge, Sn) and acceptor ions from the manufacturing process. By using non-thermal equilibrium sputtering, high-concentration doping is achieved without adding these extra components, thereby reducing manufacturing complexity and device structure complexity while achieving the desired doping concentration
3Ease of manufacture
If conventional thermal equilibrium process is used, then manufacturing process is simple, but doping concentration is limited and film thickness is reduced
Solution Approach 1:
The patent changes the thermal state parameter from equilibrium to non-equilibrium, using sputtering deposition. This enables high-concentration doping of B-site donor ions up to 40 mol% and produces thicker films without the limitations of conventional thermal equilibrium processes, while maintaining manufacturing feasibility
4Quantity of substance
If high-concentration doping is achieved by adding sintering assistants, then doping concentration increases, but film thickness is limited due to crack formation
Solution Approach 1:
The patent changes the manufacturing process parameter from thermal equilibrium to non-thermal equilibrium sputtering. This enables simultaneous achievement of high doping concentration (up to 40 mol%) and increased film thickness without crack formation, as the non-equilibrium process avoids the sintering assistant addition that causes structural degradation
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 process enables the production of ferroelectric films with superior piezoelectric performance and increased thickness, overcoming the limitations of conventional techniques by avoiding Pb defects and maintaining high ferroelectric performance.
Implementation Method 1
a non-thermal equilibrium process, specifically sputtering, is used to form PZT-based ferroelectric films
Data Source
AI summary
A ferroelectric film (40) having a columnar structure constituted by a plurality of columnar grains, and containing as a main component a perovskite oxide which has a composition expressed by a compositional formula A1+δ[(ZrxTi1-x)1-yMy]Oz, where A represents one or more A-site elements including lead (Pb) as a main component, M represents one or more of vanadium (V), niobium (Nb), tantalum (Ta), and antimony (Sb) as one or more B-site elements, zirconium (Zr) and titanium (Ti) are also B-site elements, 0 < x ≤ 0.7, 0.1 ≤ y ≤ 0.4, δ is approximately zero, z is approximately 3, and δ and z may deviate from 0 and 3, respectively, within ranges of δ and z in which the composition expressed by the compositional formula A1+δ[(ZrxTi1-x)1-yMy]Oz can substantially form a perovskite structure.