Ferroelectricity in boron-substituted aluminum nitride thin films

Hayden, John; Hossain, Mohammad Delower; Xiong, Yihuang; Ferri, Kevin; Zhu, Wanlin; Imperatore, Mario V.; Giebink, Noel C.; Trolier‐McKinstry, Susan; Dabo, Ismaïla; Maria, Jon Paul

doi:10.1103/physrevmaterials.5.044412

Cited by 94 publications

(86 citation statements)

References 31 publications

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“…Thus, the epitaxial relationship between film and template is as expected: [1-100](0001)Al 1-x Sc x N ‖ [1-100](0001)GaN. The inplane relation of the lattice orientation of GaN and sapphire is [1-100](0001)GaN ‖ [11][12][13][14][15][16][17][18][19][20](0001)Al 2 O 3 , meaning a 30° inplane rotation of the GaN with respect to the Al 2 O 3 , as visible in the pole figure and reported also in literature. [15] In addition to the low resolution wide-range RSM, high-resolution data was obtained to determine the lattice parameters of the films more accurately and draw conclusions on their strain state.…”

Section: Structural Characterizationmentioning

confidence: 63%

“…The experimental resolution of about 5 nm limited the accuracy in determining the position of the interface to ±5 nm which was placed at the onset of rising material contrast in the VDF image. The in-plane strain component was calculated from the array of [11][12][13][14][15][16][17][18][19][20] diffraction patterns describing the distance between the (01-10) planes. From the bulk of the GaN (zero strain, reference), the strain value is observed to monotonously increase when approaching the interface, forming a small plateau of ≈0.2% strain.…”

Section: Structural Characterizationmentioning

confidence: 99%

“…Therefore, with the advent of wurtzite-type ferroelectrics such as Al 1-x Sc x N and Al 1-x B x N a clear pathway toward a tunable polarization in chemically and structurally matched III-N based material systems has emerged. [12,13] The key toward realizing such all-epitaxial, all-wurtzite-type ferroelectric/semiconductor heterostructures is in the thorough understanding of their structural as well as electrical properties to allow their knowledge driven engineering. Here, we present a detailed study of these properties for Al 1-x Sc x N films with Sc contents of 19, 24, and 28 at% relative to the total amount of metal atoms (x = 0.19, 0.24, 0.28) deposited by sputter epitaxy on doped n-GaN/sapphire substrates.…”

Section: Introductionmentioning

confidence: 99%

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From Fully Strained to Relaxed: Epitaxial Ferroelectric Al_1‐_xSc_xN for III‐N Technology

Schönweger

Petraru

Islam

et al. 2022

Adv Funct Materials

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The recent emergence of wurtzite-type nitride ferroelectrics such as Al 1-x Sc x N has paved the way for the introduction of all-epitaxial, all-wurtzite-type ferroelectric III-N semiconductor heterostructures. This paper presents the first in-depth structural and electrical characterization of such an epitaxial heterostructure by investigating sputter deposited Al 1-x Sc x N solid solutions with x between 0.19 and 0.28 grown over doped n-GaN. The results of detailed structural investigations on the strain state and the initial unit-cell polarity with the peculiarities observed in the ferroelectric response are correlated. Among these, a Sc-content dependent splitting of the ferroelectric displacement current into separate peaks, which can be correlated with the presence of multiple strain states in the Al 1-x Sc x N films is discussed. Unlike in previously reported studies on ferroelectric Al 1-x Sc x N, all films thicker than 30 nm grown on the metal (M)polar GaN template feature an initial multidomain state. The results support that regions with opposed polarities in as-grown films do not result as a direct consequence of the in-plane strain distribution, but are rather mediated by the competition between M-polar epitaxial growth on an M-polar template and a deposition process that favors nitrogen (N)-polar growth.

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Section: Structural Characterizationmentioning

confidence: 63%

Section: Structural Characterizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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From Fully Strained to Relaxed: Epitaxial Ferroelectric Al_1‐_xSc_xN for III‐N Technology

Schönweger

Petraru

Islam

et al. 2022

Adv Funct Materials

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“…Recent reports demonstrate that several families of doped AlN can be made ferroelectric. [1][2][3][4] As these materials can be grown at low temperatures (often <400 °C) and have large switchable polarizations (>100 µC cm −2 ) and large bandgaps, they are of interest for nonvolatile memory applications, particularly if a means can be found to decrease the magnitude of the coercive fields. However, as shown below, for at least some growth conditions, the polarization-electric field hysteresis loop opens up progressively in initial cycling, such that the AlN-based films undergo a gradual increase in the magnitude of the remanent polarization during initial cycling, i.e., a "wake-up" of the switching process.…”

Section: Introductionmentioning

confidence: 99%

“…Recent reports demonstrate that several families of doped AlN can be made ferroelectric. [ 1–4 ] As these materials can be grown at low temperatures (often <400 °C) and have large switchable polarizations (>100 µC cm −2 ) and large bandgaps, they are of interest for nonvolatile memory applications, particularly if a means can be found to decrease the magnitude of the coercive fields.…”

Section: Introductionmentioning

confidence: 99%

Wake‐Up in Al₁₋_xB_xN Ferroelectric Films

Zhu

Hayden

et al. 2021

Adv Elect Materials

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The polarization wake‐up process is demonstrated here for ferroelectric switching in epitaxial Al0.93B0.07N films on W coated c‐axis oriented Al2O3 (sapphire) substrates. During the wake‐up process, the remanent polarization grows from ≈0 to >100 µC cm−2. As it does so, both the reversible and irreversible Rayleigh coefficients rise substantially, suggesting that the concentration of mobile interfaces that separate regions of opposite dipole orientation is increasing. The irreversible Rayleigh coefficient is very small (≈3.5 × 10−4 cm kV−1), four to five orders of magnitude below those of perovskite ferroelectric films such as PbZr0.52Ti0.48O3. These small values are consistent with the high coercive fields observed in the nitride ferroelectrics. The temperature dependence of the Rayleigh coefficients suggests that the interface motion is thermally activated. On increasing frequency, the Rayleigh coefficients drop, suggesting time‐dependent pinning processes also occur in this family of materials. With information from anisotropic etching experiments upon field‐cycling, a self‐consistent model that describes a polar domain microstructure evolution process during wake‐up is proposed.

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Unveiled Ferroelectricity in Well‐Known Non‐Ferroelectric Materials and Their Semiconductor Applications

Lee,

Cho

et al. 2023

Adv Funct Materials

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Ferroelectric materials are considered ideal for emerging memory devices owing to their characteristic remanent polarization, which can be switched by applying a sufficient electric field. However, even several decades after the initial conceptualization of ferroelectric memory, its applications are limited to a niche market. The slow advancement of ferroelectric memories can be attributed to several extant issues, such as the absence of ferroelectric materials with complementary metal–oxide–semiconductor (CMOS) compatibility and scalability. Since the 2010s, ferroelectric memories have attracted increasing interest because of newly discovered ferroelectricity in well‐established CMOS‐compatible materials, which are previously known to be non‐ferroelectric, such as fluorite‐structured (Hf,Zr)O2 and wurtzite‐structured (Al,Sc)N. With advancing material fabrication technologies, for example, accurate chemical doping and atomic‐level thickness control, a metastable polar phase, and switchable polarization with a reasonable electric field can be induced in (Hf,Zr)O2 and (Al,Sc)N. Nonetheless, various issues still exist that urgently require solutions to facilitate the use of the ferroelectric (Hf,Zr)O2 and (Al,Sc)N in emerging memory devices. Thus, ferroelectric (Hf,Zr)O2 and (Al,Sc)N are comprehensively reviewed herein, including their fundamental science and practical applications.

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Ferroelectricity in boron-substituted aluminum nitride thin films

Cited by 94 publications

References 31 publications

From Fully Strained to Relaxed: Epitaxial Ferroelectric Al_1‐_xSc_xN for III‐N Technology

From Fully Strained to Relaxed: Epitaxial Ferroelectric Al_1‐_xSc_xN for III‐N Technology

Wake‐Up in Al₁₋_xB_xN Ferroelectric Films

Unveiled Ferroelectricity in Well‐Known Non‐Ferroelectric Materials and Their Semiconductor Applications

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Ferroelectricity in boron-substituted aluminum nitride thin films

Cited by 94 publications

References 31 publications

From Fully Strained to Relaxed: Epitaxial Ferroelectric Al1‐xScxN for III‐N Technology

From Fully Strained to Relaxed: Epitaxial Ferroelectric Al1‐xScxN for III‐N Technology

Wake‐Up in Al1−xBxN Ferroelectric Films

Unveiled Ferroelectricity in Well‐Known Non‐Ferroelectric Materials and Their Semiconductor Applications

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Product

Resources

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From Fully Strained to Relaxed: Epitaxial Ferroelectric Al_1‐_xSc_xN for III‐N Technology

From Fully Strained to Relaxed: Epitaxial Ferroelectric Al_1‐_xSc_xN for III‐N Technology

Wake‐Up in Al₁₋_xB_xN Ferroelectric Films