4.6 Article

Nucleation control of high crystal quality heteroepitaxial Sc0.4Al0.6N grown by molecular beam epitaxy

Related references

Note: Only part of the references are listed.
Article Engineering, Electrical & Electronic

X-Ka Band Epitaxial ScAlN/AlN/NbN/SiC High-Overtone Bulk Acoustic Resonators

Vikrant J. Gokhale et al.

Summary: This letter presents the first demonstration of epitaxial scandium aluminum nitride (ScAlN) based high-overtone bulk acoustic resonators (epi-HBARs) with over 1600 acoustic cavity resonance modes spanning the X - Ka bands (8 GHz - 40 GHz). Key metrics for the ScAlN epi-HBARs include Q > 7000, fxQ > 10(14) Hz, and k(eff)(2) xQ(BVD) > 0.22 at cryogenic temperatures for frequencies as high as 40 GHz (>500, >6 x 10(12) Hz, >0.1 at room temperature). Such robust RF MEMS epi-HBARs with piezoelectric drive and readout are promising candidates for compact microwave/millimeter wave signal processing elements.

IEEE ELECTRON DEVICE LETTERS (2023)

Article Nanoscience & Nanotechnology

Influence of the temperature on growth by ammonia source molecular beam epitaxy of wurtzite phase ScAlN alloy on GaN

Caroline Elias et al.

Summary: For the first time, ScAlN growth has been carried out by molecular beam epitaxy using ammonia as the nitrogen precursor. The study shows that smooth surface morphology with a mean roughness below 0.5 nm can be achieved at any growth temperature. X-ray diffraction rocking curves indicate minimum full-width at half-maximum of 620 and 720 arc sec for (0002) and (1013) crystal planes at a temperature of 670°C. Additionally, high-density two-dimensional electron gases of 3-3.5 x 10(13)/cm(2) were observed in the heterostructures grown below 720°C.

APL MATERIALS (2023)

Article Engineering, Electrical & Electronic

Passivation Schemes for ScAlN-Barrier mm-Wave High Electron Mobility Transistors

Maher B. Tahhan et al.

Summary: This article presents improvements in the large-signal RF power performance at the Ka-band of gallium nitride HEMTs utilizing a scandium aluminum nitride barrier. The results showed that silicon nitride as the passivation layer increased the gain and output power, but reduced the breakdown voltage. Adding an epitaxial aluminum gallium nitride passivating layer increased the maximum bias voltage that the devices can operate at.

IEEE TRANSACTIONS ON ELECTRON DEVICES (2022)

Article Chemistry, Analytical

Growth of Highly c-Axis Oriented AlScN Films on Commercial Substrates

Jingxiang Su et al.

Summary: This work presents a method for growing highly c-axis oriented aluminum scandium nitride (AlScN) thin films on various substrates. The method is especially useful for applications like piezoelectric thin-film-based surface acoustic wave devices. The researchers use a thin AlN layer as a nucleation layer for the growth of AlScN films, which significantly improves the crystal quality of the films on different substrates.

MICROMACHINES (2022)

Article Physics, Applied

Overcoming metal-rich surface chemistry limitations of ScAlN for high electrical performance heterostructures

Zachary Engel et al.

Summary: By controlling the surface chemistry and temporary metal doses, phase-pure, metal-rich epitaxy of ScAlN was achieved, showing improved structural and electrical characteristics. The catalytic effect of Sc in metal-rich conditions was observed, resulting in varied growth rates and introducing feedback stabilization of surface chemistry.

JOURNAL OF APPLIED PHYSICS (2022)

Article Engineering, Electrical & Electronic

Controlling Residual Stress and Suppression of Anomalous Grains in Aluminum Scandium Nitride Films Grown Directly on Silicon

Rossiny Beaucejour et al.

Summary: This study demonstrates the deposition of high Sc alloying levels AlScN films on silicon with controlled stress and without the formation of anomalous grains (AOGs) using reactive sputtering. It is shown that a gradient seed layer and proper process gas mixture can inhibit the formation of AOGs even at high Sc alloying levels. The total flow is found to control the average film stress, while the process gas mixture mainly affects the density of AOG formation. Bulk acoustic wave resonators fabricated from low stress and AOG-free Al0.68Sc0.32N films grown directly on Si exhibit high frequency operation, high electromechanical coupling, and high quality factors.

JOURNAL OF MICROELECTROMECHANICAL SYSTEMS (2022)

Proceedings Paper Engineering, Electrical & Electronic

FerroHEMTs: High-Current and High-Speed All-Epitaxial AlScN/GaN Ferroelectric Transistors

J. Casamento et al.

Summary: This study reports the first observation of ferroelectric gating in AlScN barrier wide-bandgap nitride transistors. These new FerroHEMT devices, realized by direct epitaxial growth, represent a new class of ferroelectric transistors where the semiconductor itself is polar and the crystalline ferroelectric barrier is lattice-matched to the substrate. The FerroHEMTs in this study use the thinnest nitride high-K and ferroelectric barriers to date, achieving the highest on-currents at 4 A/mm and the highest speed AlScN transistors with f(MAX) > 150 GHz observed in any ferroelectric transistor. These FerroHEMTs exhibit hysteretic I-d - V-gs loops with subthreshold slopes below the Boltzmann limit. A control AlN barrier HEMT does not show any hysteresis or sub-Boltzmann behavior. Furthermore, these results introduce the first epitaxial high-K and ferroelectric barrier technology to RF and mm-wave electronics and are also of interest for combining memory and logic functionalities in digital electronics.

2022 INTERNATIONAL ELECTRON DEVICES MEETING, IEDM (2022)

Article Acoustics

Passive High Power RF Comb Filters Using Epitaxial GaN/NbN/SiC HBARs

Vikrant J. Gokhale et al.

Summary: This report demonstrates the first passive RF comb filters made using epi-HBAR technology, with multiple sharp filter passbands suitable for high-power RF operation, and potential to replace larger off-chip or discrete-component comb filters.

IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL (2021)

Article Nanoscience & Nanotechnology

Strongly enhanced second-order optical nonlinearity in CMOS-compatible Al1-xScxN thin films

Valerie Yoshioka et al.

Summary: Silicon photonics has enabled large-scale production of integrated optical devices for various applications, but faces challenges when used in nonlinear devices. Scandium-doped aluminum nitride thin films exhibit enhanced optical second-order susceptibility, offering potential advantages for developing CMOS-compatible devices with strong nonlinearity.

APL MATERIALS (2021)

Article Chemistry, Multidisciplinary

Post-CMOS Compatible Aluminum Scandium Nitride/2D Channel Ferroelectric Field-Effect-Transistor Memory

Xiwen Liu et al.

Summary: The combination of FE-AlScN and 2D MoS2 shows promising characteristics for embedded memory and memory-based computing architectures, with a high ON/OFF ratio, stable memory states, and state retention.

NANO LETTERS (2021)

Article Physics, Applied

Strongly temperature dependent ferroelectric switching in AlN, Al1-xScxN, and Al1-xBxN thin films

Wanlin Zhu et al.

Summary: This study reveals the temperature dependence of ferroelectric switching in Al0.84Sc0.16N, Al0.93B0.07N, and AlN thin films, showing strong temperature dependence on polarization reversal and coercive field, while minimal temperature dependence on remanent polarization values. The relative permittivity increased within a certain temperature range, and polarization reversal was confirmed through piezoelectric coefficient analysis and chemical etching. Models based on thermal activation suggest a distribution of pinning sites or nucleation barriers regulates the switching behavior with an average activation energy near 28 meV.

APPLIED PHYSICS LETTERS (2021)

Article Physics, Applied

Fully epitaxial ferroelectric ScAlN grown by molecular beam epitaxy

Ping Wang et al.

Summary: Ferroelectricity has been successfully demonstrated in ScxAl1-xN epitaxial films grown on GaN templates by molecular beam epitaxy, showing distinct polarization switching and excellent properties, such as a high coercive field and long polarization retention time. This achievement opens up possibilities for integrating high-performance ferroelectric functionality into established semiconductor platforms for various electronic and photonic device applications.

APPLIED PHYSICS LETTERS (2021)

Article Materials Science, Multidisciplinary

Metal-Organic Chemical Vapor Deposition of Aluminum Scandium Nitride

Stefano Leone et al.

PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS (2020)

Article Physics, Applied

Metalorganic chemical vapor phase deposition of AlScN/GaN heterostructures

Jana Ligl et al.

JOURNAL OF APPLIED PHYSICS (2020)

Article Engineering, Electrical & Electronic

Ferroelectric Switching in Sub-20 nm Aluminum Scandium Nitride Thin Films

Dixiong Wang et al.

IEEE ELECTRON DEVICE LETTERS (2020)

Article Nanoscience & Nanotechnology

Band Alignment of ScxAl1-xN/GaN Heterojunctions

Eric N. Jin et al.

ACS APPLIED MATERIALS & INTERFACES (2020)

Article Physics, Applied

AlScN: A III-V semiconductor based ferroelectric

Simon Fichtner et al.

JOURNAL OF APPLIED PHYSICS (2019)

Article Physics, Applied

Investigation of growth parameters for ScAlN-barrier HEMT structures by plasma-assisted MBE

Kathrin Frei et al.

JAPANESE JOURNAL OF APPLIED PHYSICS (2019)

Article Materials Science, Multidisciplinary

Thickness dependence of Al0.88Sc0.12N thin films grown on silicon

Katherine Knisely et al.

THIN SOLID FILMS (2019)

Article Materials Science, Multidisciplinary

Abnormal Grain Growth in AlScN Thin Films Induced by Complexion Formation at Crystallite Interfaces

Cosmin Silviu Sandu et al.

PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE (2019)

Proceedings Paper Engineering, Electrical & Electronic

High Power Density ScAlN-Based Heterostructure FETs for mm-Wave Applications

Thomas E. Kazior et al.

2019 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM (IMS) (2019)

Article Engineering, Manufacturing

Epitaxial ScAlN Etch-Stop Layers Grown by Molecular Beam Epitaxy for Selective Etching of AlN and GaN

Matthew T. Hardy et al.

IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING (2017)

Article Materials Science, Coatings & Films

XeF2 etching of epitaxial Nb2N for lift-off or micromachining of III-N materials and devices

Brian P. Downey et al.

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A (2017)

Article Physics, Applied

Epitaxial ScAlN grown by molecular beam epitaxy on GaN and SiC substrates

Matthew T. Hardy et al.

APPLIED PHYSICS LETTERS (2017)

Article Physics, Condensed Matter

Piezoelectric coefficients and spontaneous polarization of ScAlN

Miguel A. Caro et al.

JOURNAL OF PHYSICS-CONDENSED MATTER (2015)

Article Crystallography

Molecular beam epitaxy of ferromagnetic epitaxial GdN thin films

F. Natali et al.

JOURNAL OF CRYSTAL GROWTH (2014)

Article Chemistry, Physical

ScGaN and ScAlN: emerging nitride materials

M. A. Moram et al.

JOURNAL OF MATERIALS CHEMISTRY A (2014)

Article Acoustics

High-Performance Surface Acoustic Wave Resonators in the 1 to 3 GHz Range Using a ScAlN/6H-SiC Structure

Ken-ya Hashimoto et al.

IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL (2013)

Article Physics, Applied

Elastic constants and critical thicknesses of ScGaN and ScAlN

S. Zhang et al.

JOURNAL OF APPLIED PHYSICS (2013)

Article Physics, Applied

Tunable optoelectronic and ferroelectric properties in Sc-based III-nitrides

Siyuan Zhang et al.

JOURNAL OF APPLIED PHYSICS (2013)

Article Physics, Applied

Microstructure and dielectric properties of piezoelectric magnetron sputtered w-ScxAl1-xN thin films

Agne Zukauskaite et al.

JOURNAL OF APPLIED PHYSICS (2012)

Article Materials Science, Multidisciplinary

Piezoelectric aluminum nitride thin films for microelectromechanical systems

Gianluca Piazza et al.

MRS BULLETIN (2012)

Article Physics, Applied

Increased electromechanical coupling in w-ScxAl1-xN

Gunilla Wingqvist et al.

APPLIED PHYSICS LETTERS (2010)

Article Physics, Multidisciplinary

Origin of the Anomalous Piezoelectric Response in Wurtzite ScxAl1-xN Alloys

Ferenc Tasnadi et al.

PHYSICAL REVIEW LETTERS (2010)

Article Physics, Applied

Strain-induced polarization in wurtzite III-nitride semipolar layers

A. E. Romanov et al.

JOURNAL OF APPLIED PHYSICS (2006)

Article Engineering, Electrical & Electronic

High power blue-violet InGaN laser diodes grown on bulk GaN substrates by plasma-assisted molecular beam epitaxy

C Skierbiszewski et al.

SEMICONDUCTOR SCIENCE AND TECHNOLOGY (2005)

Article Engineering, Electrical & Electronic

Uniformity and control of surface morphology during growth of GaN by molecular beam epitaxy

C Poblenz et al.

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B (2005)

Article Materials Science, Coatings & Films

Thickness dependence of the properties of highly c-axis textured AlN thin films

F Martin et al.

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A (2004)

Article Physics, Applied

Stress relaxation in mismatched layers due to threading dislocation inclination

AE Romanov et al.

APPLIED PHYSICS LETTERS (2003)