Method of controlling coupling coefficient of Aluminum Scandium Nitride deposition in high volume production

Mishin, Sergey; Gutkin, Michael; Bizyukov, A. A.; Sleptsov, V. V.

doi:10.1109/eftf-ifc.2013.6702105

Cited by 11 publications

(4 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recent work has focused on incorporation of these alloys into devices such as energy harvesters [16], ultrasonic transducers [17], and primarily in acoustic resonators [18][19][20][21][22][23][24][25], enabling alternative operation modes [26][27][28]. From a deployment perspective, the continued work on processing conditions highlights the difficulty of achieving high-quality materials with x > 0.2, where misoriented grains degrade the macroscopic piezoelectric response [29][30][31][32]. In parallel with the experimental work, the theory community progressed from the previously mentioned firstprinciples polymorph energies [3] to first-principles mixing energies [4,33], lattice calculations [34], property calculations [35][36][37], and the effects of cation ordering on performance [38].…”

Section: Introductionmentioning

confidence: 99%

Implications of heterostructural alloying for enhanced piezoelectric performance of (Al,Sc)N

Talley

Millican

Mangum

et al. 2018

Phys. Rev. Materials

View full text Add to dashboard Cite

An understanding of the heterostructural implications on alloying in the aluminum nitride-scandium nitride system (Al 1−x Sc x N) can highlight opportunities and design principles for enhancing desired material properties by leveraging nonequilibrium states. The fundamental thermodynamics, and therefore composition-and structuredependent mechanisms, underlying property evolution in this system have not been fully described, despite significant recent efforts driven by interest in enhanced piezoelectric performance. Practical realization of these enhanced properties, however, is hindered by the strong driving thermodynamic driving force for phase separation in the system, highlighting the need for increased study into the role of heterostructural alloying on the thermodynamics and composition-structure-property relationships in this system. With this need in mind, ab initio computed alloy thermodynamics and properties are compared to combinatorial thin-film synthesis and characterization to develop a more complete picture of the structure and property evolution across the Al 1−x Sc x N composition space. The combination of structural frustration and a flattened free-energy landscape lead to substantial increases in electromechanical response. The energy scale of alloy metastability is found to be much larger than previously reported, helping to explain difficulties in achieving homogeneous materials with high scandium concentration. Scandium substitution for aluminum softens the wurtzite crystal lattice, and energetic proximity to the competing hexagonal boron-nitride structure enhances the piezoelectric stress coefficient. Overall, this work provides insight into the understanding of the structure-processing-property relationships in the Al 1−x Sc x N system, suggests material design strategies for even greater property enhancements, and demonstrates the increased property tunability and underexplored nature of nonequilibrium heterostructural alloys.

show abstract

Section: Introductionmentioning

confidence: 99%

Implications of heterostructural alloying for enhanced piezoelectric performance of (Al,Sc)N

Talley

Millican

Mangum

et al. 2018

Phys. Rev. Materials

View full text Add to dashboard Cite

show abstract

“…Akiyama et al reported that substitution of aluminum (Al) by scandium (Sc) increases the piezoelectric coefficient d 33 of scandium aluminum nitride (Sc x Al 1−x N) thin film at x = 0.43 by approximately 400% in comparison with pure AlN [5]- [14]. This experimental result was explained by first-principles calculations in which the observed large increase in d 33 is caused by an intrinsic alloying effect and is related to an increase in the piezoelectric constant (e 33 ) in conjunction with a decrease in the elastic constant (C 33 ) [7].…”

mentioning

confidence: 99%

Highly piezoelectric co-doped AlN thin films for wideband FBAR applications

Yokoyama

Iwazaki

Onda

et al. 2015

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

View full text Add to dashboard Cite

We report piezoelectric materials composed of charge-compensated co-doped (Mg, β)(x)Al(1-x)N (β = Zr or Hf) thin films. The effect of the dopant element into AlN on the crystal structure, and piezoelectric properties of co-doped AlN was determined on the basis of a first-principles calculation, and the theoretical piezoelectric properties were confirmed by experimentally depositing thin films of magnesium (Mg) and zirconium (Zr) co-doped AlN (Mg-Zr-doped AlN). The Mg-Zrdoped AlN thin films were prepared on Si (100) substrates by using a triple-radio-frequency magnetron reactive co-sputtering system. The crystal structures and piezoelectric coefficients (d33) were investigated as a function of the concentrations, which were measured by X-ray diffraction and a piezometer. The results show that the d33 of Mg-Zr-doped AlN at total Mg and Zr concentrations (both expressed as β) of 0.35 was 280% larger than that of pure AlN. The experimentally measured parameter of the crystal structure and d33 of Mg-Zr-doped AlN (plotted as functions of total Mg and Zr concentrations) were in very close agreement with the corresponding values obtained by the first-principle calculations. Thin film bulk acoustic wave resonators (FBAR) employing (Mg,Zr)0.13Al0.87N and (Mg, Hf)0.13 Al0.87N as a piezoelectric thin film were fabricated, and their resonant characteristics were evaluated. The measured electromechanical coupling coefficient increased from 7.1% for pure AlN to 8.5% for Mg-Zr-doped AlN and 10.0% for Mg- Hf-doped AlN. These results indicate that co-doped (Mg, β)(x)Al(1-x)N (β = Zr or Hf) films have potential as piezoelectric thin films for wideband RF applications.

show abstract

“…Recently, Akiyama et al reported that aluminum (Al) substitution by scandium (Sc) allows increases in the piezoelectric coefficient d 33 of scandium aluminum nitride (Sc x Al 1-x N) thin film at x = 0.43 by approximately 400% in reference to pure AlN [5][6][7][8][9][10][11][12][13][14]. This experimental result can be explained by first-principles calculations in which the observed large increase in d 33 was caused by an intrinsic alloying effect and was related to an increase in the piezoelectric constant (e 33 ) in conjunction with a decrease in the elastic constant (c 33 ) [7].…”

Section: Introductionmentioning

confidence: 99%

Highly piezoelectric co-doped AlN thin films for wideband FBAR applications

Yokoyama

Iwazaki

Onda

et al. 2014

2014 IEEE International Ultrasonics Symposium

View full text Add to dashboard Cite

In this paper, we report new piezoelectric materials composed of charge-compensated co-doped (Mg, ) x Al 1-x N ( = Zr or Hf). The effect of the dopant element into AlN on chemical stability, crystal structure, and piezoelectric property of co-doped AlN was determined on the basis of first-principles calculation, and the theoretical piezoelectric property was confirmed by experimentally depositing thin films of magnesium (Mg) and zirconium (Zr) co-doped AlN (Mg-Zr-doped AlN). The Mg-Zrdoped AlN thin films were prepared on Si (100) substrates by a triple-radio-frequency magnetron reactive co-sputtering system. The crystal structures and piezoelectric coefficients (d 33 ) of the films were investigated as a function of their concentrations, which were measured by X-ray diffraction and a piezometer. The investigation results show that d 33 of Mg-Zr-doped AlN at total Mg and Zr concentrations (both expressed as x) of 0.35 is 280% larger than that of pure AlN. The experimentally measured parameter of the crystal structure and d 33 of Mg-Zr-doped AlN (plotted as functions of total Mg and Zr concentrations) are in very close agreement with the corresponding values obtained by first-principle calculations. Thin film bulk acoustic wave resonators (FBARs) employing (Mg,Zr) 0.13 Al 0.87 N and (Mg,Hf) 0.13 Al 0.87 N as a piezoelectric thin film were fabricated, and their resonant characteristics were evaluated. As a result, the measured electromechanical coupling coefficient was found to increase from 7.1% (for pure AlN) to 8.5% for Mg-Zr-doped AlN and 10.0% for Mg-Hf-doped AlN. These results indicate that codoped (Mg, ) x Al 1-x N ( = Zr or Hf) films have potential as piezoelectric thin films for wideband RF applications.

show abstract

Method of controlling coupling coefficient of Aluminum Scandium Nitride deposition in high volume production

Cited by 11 publications

References 5 publications

Implications of heterostructural alloying for enhanced piezoelectric performance of (Al,Sc)N

Implications of heterostructural alloying for enhanced piezoelectric performance of (Al,Sc)N

Highly piezoelectric co-doped AlN thin films for wideband FBAR applications

Highly piezoelectric co-doped AlN thin films for wideband FBAR applications

Contact Info

Product

Resources

About