(Na_xK_0.98-xLi_0.02)(Nb_0.8Ta_0.2)O₃ Lead-Free Piezoelectric Ceramics

Abstract

Pattern printability was examined while varying the thickness of a multilayer mask blank by simulation. The variations were related to the total thickness and the monolayer thickness of 40 Si/Mo bilayers. Printability was evaluated by using the pattern edge contrast for a binary mask and an attenuated phase shift mask (att-PSM). The total thickness variation degrades pattern edge contrast with decreasing exposure energy on a wafer. The phase shift between multilayer and absorber on a mask differs depending on the total thickness variation. The phase shift due to the total thickness variation gives rise to the focal position shift as a function of exposure wavelength for both the binary mask and the att-PSM. The phase shift and the focal position shift of the binary mask are different from those of the att-PSM. Monolayer thickness variation did not affect the printability of both the binary mask and the att-PSM.

Effects of the Domain Size on Local d33 in Tetragonal (Na0.53K0.45Li0.02)(Nb0.8Ta0.2)O3 Ceramics

“…. The XRD result demonstrates that the NKLNT ceramics correspond to a pure tetragonal perovskite structure without any secondary phase, as in a previous report . The corresponding piezoelectric properties with the remnant polarization ( P r ), coercive field ( E c ) and piezoelectric coefficient ( d 33 ) were 13.3 μC/cm 2 , 1.3 kV/cm, and 280 pC/N, respectively, are indicated in Table .…”

“…This result is in agreement with our XRD and FE‐SEM analysis, although it is generally in contrast to most previous studies of NKN‐based ceramics, where the orthorhombic phase was mainly found. The difference originates substantially from the Na + rich content (53 mol%) on A sites of the Li‐ and Ta‐modified NKN ceramics, leading to a phase transformation from orthorhombic to tetragonal, as discussed earlier by Kim et al …”

“…However, lead‐free NKN ceramics generally show low piezoelectric properties compared to PZT system ceramics . Many researchers have tried to improve the piezoelectric properties via the chemical modification of the NKN system, such as replacing the A and/or B sites of the ABO 3 perovskite structure with Li and Ta . However, the achievement of piezoelectric properties in NKN ceramics has not led to a replacement for PZT.…”

Temperature Dependent Piezoelectric Properties of Lead-Free (1-x)K0.6Na0.4NbO3–xBiFeO3 Ceramics

“…The sintering temperature of K 0.5 Na 0.5 NbO 3 is close to its melting-point and consequently it is not easy to achieve a dense ceramic without liquid phase sintering (Wang and Li, 2012). It has been reported (Zhen and Li, 2007;Kim et al, 2009) that grain size and core-shell structures in such grains influence piezoelectric properties. The BF content is affecting the sintering temperature, for larger contents of BF the conditions don't favor formation of large cluster and the constituent grains are disintegrated, thereby showing smaller grains.…”

(K,Na)NbO3‐Based Lead‐Free Piezoceramics: Fundamental Aspects, Processing Technologies, and Remaining Challenges

“…Appearance of liquid phase during sintering promotes the AGG behavior as well as secondary phase . Generally, grain growth is classified into two types: normal and abnormal (exaggerated) grain growth .…”