Stability and residual stresses of sputtered wurtzite AlScN thin films

Österlund, Elmeri; Ross, Glenn; Miguel, A.; Paulasto‐Kröckel, Mervi; Hollmann, Andreas; Klaus, Manuela; Meixner, M.; Genzel, Christoph; Koppinen, P. J.; Pensala, Tuomas; Žukauskaitė, Agnė; Trębala, Michał

doi:10.1103/physrevmaterials.5.035001

Cited by 25 publications

(22 citation statements)

References 47 publications

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“…Using the c / a data from the work presented by Österlund et al [ 45 ], and considering the isotropic etching of the

plane, the theoretical sidewall angle φ can be plotted against the experimental value ( Figure 10 ).…”

Section: Results and Analysismentioning

confidence: 99%

“…High-quality polycrystalline Al 1−x Sc x N films can be deposited with physical vapor deposition (PVD) methods such as magnetron sputtering. This method features a high deposition rate, low growth temperature, and the capability of up-scaling in substrate size [ 42 , 43 , 44 , 45 , 46 ], and has been adopted by a variety of tool manufacturers for industrial mass production [ 47 ].…”

Section: Methodsmentioning

confidence: 99%

“…Hence, during the anisotropic etching process, the exposed 1123 slip edges between the boundary of the 1011 planes forms the facets that follow the 1212 of the hexagonal crystal structure, behind which lateral etching ceases advancing (Figure 8). Moreover, for a Hexagonal Close-Packed (HCP) unit cell with an axis length c/a, the sidewall angle, θ (Figure 9), of the {1212} facets as a function of lattice length can be calculated as 𝜃 = arctan(𝑐/𝑎): Using the c/a data from the work presented by Ö sterlund et al [45], and considering the isotropic etching of the {1011} plane, the theoretical sidewall angle φ can be plotted against the experimental value (Figure 10). Moreover, for a Hexagonal Close-Packed (HCP) unit cell with an axis length c/a, the sidewall angle, θ (Figure 9), of the {1212} facets as a function of lattice length can be calculated as 𝜃 = arctan(𝑐/𝑎): Using the c/a data from the work presented by Ö sterlund et al [45], and considering the isotropic etching of the {1011} plane, the theoretical sidewall angle φ can be plotted against the experimental value (Figure 10).…”

Section: ° 567 °mentioning

confidence: 99%

“…Moreover, for a Hexagonal Close-Packed (HCP) unit cell with an axis length c/a, the sidewall angle, θ (Figure 9), of the {1212} facets as a function of lattice length can be calculated as 𝜃 = arctan(𝑐/𝑎): Using the c/a data from the work presented by Ö sterlund et al [45], and considering the isotropic etching of the {1011} plane, the theoretical sidewall angle φ can be plotted against the experimental value (Figure 10). Moreover, for a Hexagonal Close-Packed (HCP) unit cell with an axis length c/a, the sidewall angle, θ (Figure 9), of the {1212} facets as a function of lattice length can be calculated as 𝜃 = arctan(𝑐/𝑎): Using the c/a data from the work presented by Ö sterlund et al [45], and considering the isotropic etching of the {1011} plane, the theoretical sidewall angle φ can be plotted against the experimental value (Figure 10). Using the c/a data from the work presented by Österlund et al [45], and considering the isotropic etching of the 1011 plane, the theoretical sidewall angle ϕ can be plotted against the experimental value (Figure 10).…”

Section: ° 567 °mentioning

confidence: 99%

“…Moreover, for a Hexagonal Close-Packed (HCP) unit cell with an axis length c/a, the sidewall angle, θ (Figure 9), of the {1212} facets as a function of lattice length can be calculated as 𝜃 = arctan(𝑐/𝑎): Using the c/a data from the work presented by Ö sterlund et al [45], and considering the isotropic etching of the {1011} plane, the theoretical sidewall angle φ can be plotted against the experimental value (Figure 10). Using the c/a data from the work presented by Österlund et al [45], and considering the isotropic etching of the 1011 plane, the theoretical sidewall angle ϕ can be plotted against the experimental value (Figure 10). The absolute value of the experimental and theoretical angles follows the same trajectory with a parabolic downtrend with increasing Sc concentration until the Sc concentration exceeds 40%.…”

Section: ° 567 °mentioning

confidence: 99%

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Vertical and Lateral Etch Survey of Ferroelectric AlN/Al1−xScxN in Aqueous KOH Solutions

et al. 2022

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Due to their favorable electromechanical properties, such as high sound velocity, low dielectric permittivity and high electromechanical coupling, Aluminum Nitride (AlN) and Aluminum Scandium Nitride (Al1−xScxN) thin films have achieved widespread application in radio frequency (RF) acoustic devices. The resistance to etching at high scandium alloying, however, has inhibited the realization of devices able to exploit the highest electromechanical coupling coefficients. In this work, we investigated the vertical and lateral etch rates of sputtered AlN and Al1−xScxN with Sc concentration x ranging from 0 to 0.42 in aqueous potassium hydroxide (KOH). Etch rates and the sidewall angles were reported at different temperatures and KOH concentrations. We found that the trends of the etch rate were unanimous: while the vertical etch rate decreases with increasing Sc alloying, the lateral etch rate exhibits a V-shaped transition with a minimum etch rate at x = 0.125. By performing an etch on an 800 nm thick Al0.875Sc0.125N film with 10 wt% KOH at 65 °C for 20 min, a vertical sidewall was formed by exploiting the ratio of the 1011¯ planes and 11¯00 planes etch rates. This method does not require preliminary processing and is potentially beneficial for the fabrication of lamb wave resonators (LWRs) or other microelectromechanical systems (MEMS) structures, laser mirrors and Ultraviolet Light-Emitting Diodes (UV-LEDs). It was demonstrated that the sidewall angle tracks the trajectory that follows the 1¯212¯ of the hexagonal crystal structure when different c/a ratios were considered for elevated Sc alloying levels, which may be used as a convenient tool for structure/composition analysis.

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“…Using the c / a data from the work presented by Österlund et al [ 45 ], and considering the isotropic etching of the

plane, the theoretical sidewall angle φ can be plotted against the experimental value ( Figure 10 ).…”

Section: Results and Analysismentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: ° 567 °mentioning

confidence: 99%

Section: ° 567 °mentioning

confidence: 99%

“…Moreover, for a Hexagonal Close-Packed (HCP) unit cell with an axis length c/a, the sidewall angle, θ (Figure 9), of the {1212} facets as a function of lattice length can be calculated as 𝜃 = arctan(𝑐/𝑎): Using the c/a data from the work presented by Ö sterlund et al [45], and considering the isotropic etching of the {1011} plane, the theoretical sidewall angle φ can be plotted against the experimental value (Figure 10). Using the c/a data from the work presented by Österlund et al [45], and considering the isotropic etching of the 1011 plane, the theoretical sidewall angle ϕ can be plotted against the experimental value (Figure 10). The absolute value of the experimental and theoretical angles follows the same trajectory with a parabolic downtrend with increasing Sc concentration until the Sc concentration exceeds 40%.…”

Section: ° 567 °mentioning

confidence: 99%

See 3 more Smart Citations

Vertical and Lateral Etch Survey of Ferroelectric AlN/Al1−xScxN in Aqueous KOH Solutions

et al. 2022

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Enhanced Mechanical, Thermal and Electrical Properties of High‐Entropy HfMoNbTaTiVWZr Thin Film Metallic Glass and its Nitrides

et al. 2022

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Amorphous metallic alloys or bulk metallic glasses (BMGs) are non-crystalline metals that lack long-range order. The disordered atomic structure and absence of grain boundaries in BMGs results in giving them good soft-magnetic properties and excellent mechanical properties with high elastic limits and specific strength, as well as highly corrosion and wear-resistant properties. [1] Different BMGs based on Zr, Cu, Ti, Fe, Pd, Pt, and Au systems have been developed thus far. [1] However, one of the major drawbacks of BMGs is their low ductility. The concept of BMGs has been explored recently in developing thin film metallic glasses (TFMG) from vapor-to-solid phase deposition using binary or ternary compositions. [2,3] Furthermore, the composition window for achieving amorphous films is much wider than that achieved from BMGs using rapid casting as the resulting material from vapor-to-solid deposition is farther from equilibrium than the material produced by the liquid-to-solid casting process. [4] In addition to high strength, the resulting TFMG brings improved ductility and good formability. [4] Such thin films are useful in applications, such as biomedical use, [5] increasing fatigue properties of commercial blades, [6] microelectronics and optoelectronics, [7] wear resistance [8] and microelectro-mechanical system (MEMS) devices. [9]

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Enhancement of Piezoelectric Response in Yttrium Aluminum Nitride (Y_xAl_1‐xN) Thin Films

Pandit,

Schneider,

Schwarz

et al. 2023

Adv Eng Mater

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Alloying rare earth elements into aluminum nitride (AlN) thin films to increase the piezoelectric response has gained a lot of attention in the past few years. Many rare earth elements were investigated in which scandium alloying has resulted in the highest piezoelectric response for AlN. At the same time, researchers have also theoretically explored yttrium alloying as a feasible and economical alternative to scandium. In this paper, we demonstrate for the first time experimentally the increase of the piezoelectric response of sputter‐deposited YxAl1–xN thin films as a function of increasing yttrium concentration as predicted by density functional theory calculations. By using differently manufactured targets, YxAl1–xN thin films with four different yttrium alloying concentrations (9, 12, 15 and 20 at%.) are synthesized. Detailed thin film analysis is carried out and the highest value of d 33 measured is 12 pC/N for Y0.2Al0.8N, which is a 250 % increase compared to pure AlN. Even more, the Young’s modulus decreases with increasing yttrium concentration in excellent agreement with theoretical predictions. Finally, Y0.15Al0.85N and Y0.2Al0.8N layers show high crystalline stability in pure oxygen environment up to 800˚C, demonstrating high oxidation resistance even under harsh environmental conditions.This article is protected by copyright. All rights reserved.

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Stability and residual stresses of sputtered wurtzite AlScN thin films

Cited by 25 publications

References 47 publications

Vertical and Lateral Etch Survey of Ferroelectric AlN/Al1−xScxN in Aqueous KOH Solutions

Vertical and Lateral Etch Survey of Ferroelectric AlN/Al1−xScxN in Aqueous KOH Solutions

Enhanced Mechanical, Thermal and Electrical Properties of High‐Entropy HfMoNbTaTiVWZr Thin Film Metallic Glass and its Nitrides

Enhancement of Piezoelectric Response in Yttrium Aluminum Nitride (Y_xAl_1‐xN) Thin Films

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Stability and residual stresses of sputtered wurtzite AlScN thin films

Cited by 25 publications

References 47 publications

Vertical and Lateral Etch Survey of Ferroelectric AlN/Al1−xScxN in Aqueous KOH Solutions

Vertical and Lateral Etch Survey of Ferroelectric AlN/Al1−xScxN in Aqueous KOH Solutions

Enhanced Mechanical, Thermal and Electrical Properties of High‐Entropy HfMoNbTaTiVWZr Thin Film Metallic Glass and its Nitrides

Enhancement of Piezoelectric Response in Yttrium Aluminum Nitride (YxAl1‐xN) Thin Films

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Product

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Enhancement of Piezoelectric Response in Yttrium Aluminum Nitride (Y_xAl_1‐xN) Thin Films