Potassium Sodium Niobate Sputtering Target Dopant Uniformity
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Solution Overview
Problem
The challenge is to suppress the generation of particles during the sputtering deposition of potassium sodium niobate targets, which is exacerbated by the addition of dopants due to in-plane compositional variations caused by hygroscopicity and volatility of the dopant materials, affecting the stability and efficiency of the sputtering process.
Innovation Solution
A potassium sodium niobate sputtering target with a dopant variation coefficient of 0.12 or less is developed, incorporating elements like Li, Mg, Ca, Sr, and rare earth metals, which are added to improve piezoelectric properties and sinterability, ensuring uniform composition and reduced particle generation by controlling the dopant concentration and K/Na ratio, and achieving high relative density and flexural strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dopant is added to the potassium sodium niobate sputtering target to improve piezoelectric properties, then the piezoelectric performance is enhanced, but the number of particles generated during deposition increases
Solution Approach 1:
The invention changes the chemical composition parameters by selecting specific dopant elements (Li, Mg, Ca, Sr, Ba, Bi, Sb, V, In, Ta, Mo, W, Cr, Ti, Zr, Hf, rare earth elements, Cu, Zn, Ag, Mn, Fe, Co, Ni, Al, Si, Ge, Sn, or Ga) and precisely controlling their concentration (0.01-5 at%). This parameter optimization allows maintaining piezoelectric performance while suppressing particle generation through improved compositional uniformity.
Solution Approach 2:
The invention applies local quality by ensuring uniform dopant distribution throughout the sputtering target material. By achieving homogeneous local composition (variation coefficient of 0.12 or less), the dopant benefits are realized throughout the entire target without localized particle generation issues.
2Reliability
If dopant materials with hygroscopicity and volatility are used to improve piezoelectric properties, then the piezoelectric performance is enhanced, but in-plane compositional variations occur affecting sputtering stability
Solution Approach 1:
The invention applies preliminary action by pre-treating the dopant materials and optimizing the sintering process before sputtering. The dopants are incorporated into the target during controlled sintering at 900-1350°C, creating a stable, homogeneous structure that resists compositional variations during subsequent sputtering deposition.
Solution Approach 2:
The invention changes processing parameters including sintering temperature (900-1350°C), dopant concentration (0.01-5 at%), and target density (relative density 90% or more) to achieve compositional stability. These parameter optimizations ensure that hygroscopic and volatile dopants remain uniformly distributed during sputtering.
3Reliability
If the dopant concentration is increased to enhance piezoelectric properties, then the piezoelectric performance is improved, but the variation coefficient of dopant concentration increases leading to more particle generation
Solution Approach 1:
The invention optimizes the dopant concentration parameter within the specific range of 0.01-5 at%, which is sufficient to enhance piezoelectric properties without causing excessive variation. This parameter optimization, combined with controlled sintering, maintains the variation coefficient at 0.12 or less, suppressing particle generation while achieving desired piezoelectric performance.
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 effectively suppresses particle generation during deposition, stabilizes the sputtering process, and enhances the deposition rate and productivity, while maintaining the piezoelectric properties close to those of lead-based PZT, making it suitable for lead-free actuator or sensor applications.
Implementation Method 1
Japanese Patent Application Publication Nos. 2017-179415 and 2017-179416 describe production of a piezoelectric thin film of potassium sodium niobite by using a sputtering target
Implementation Method 2
The sputtering target is formed from a sintered body which is obtained by calcinating a Na2CO3 powder, a K2CO3 powder, and a Nb2O5 powder and thereafter press molding the calcined powders, and burning the molded product in an air atmosphere at 950 to 1350° C.
Data Source
AI summary
A sputtering target formed from a potassium sodium niobate sintered body to which a dopant has been added; as a dopant, the sputtering target includes one or more types among Li, Mg, Ca, Sr, Ba, Bi, Sb, V, In, Ta, Mo, W, Cr, Ti, Zr, Hf, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Cu, Zn, Ag, Mn, Fe, Co, Ni, Al, Si, Ge, Sn, and Ga; and a variation coefficient of a dopant concentration in a plane of the sputtering target is 0.12 or less. In terms of suppressing the generation of particles, provided is a sputtering target which is formed from a sintered body that includes potassium sodium niobate and to which a dopant has been added.