Ferroelectric switching is unambigiously demonstrated for the first time in a III-V semiconductor based material: AlScN -- A discovery which could help to satisfy urgent demand thin film ferroelectrics with high performance and good technological compatibility generic technology arises from multitude of memory, micro/nano-actuator emerging applications on controlling electrical polarization. The appearance ferroelectricity can be related continuous distortion original wurtzite-type crystal...

Ferroelectrics are a class of materials that possess variety interactions between electrical, mechanical, and thermal properties have enabled wealth functionalities. To realize integrated systems, the integration these functionalities into semiconductor processes is necessary. this end, complexity well-known ferroelectric materials, e.g., perovskite class, causes severe issues limit its applications in systems. The discovery ferroelectricity hafnium oxide-based brought renewed interest field...

Abstract Wurtzite‐type Al 1− x Sc N solid solutions grown by metal organic chemical vapor deposition are for the first time confirmed to be ferroelectric. The film with 230 nm thickness and = 0.15 exhibits a coercive field of 5.5 MV cm −1 at measurement frequency 1.5 kHz. single crystal quality homogeneous composition X‐ray diffraction spectroscopic methods such as flight secondary ion mass spectrometry. Annular bright scanning transmission electron microscopy serves prove ferroelectric...

Enhancing the piezoelectric activity of AlN by partially substituting Al with Sc to form Al1–xScxN is a promising approach improve performance micro-electromechanical systems. Here, we present evidence an instability in morphology Al1–xScxN, which originates at, or close to, substrate/Al1–xScxN interface and becomes more pronounced as content increased. Based on Transmission electron microscopy, piezoresponse force X-ray diffraction, SEM analysis, it identified be incipient formation (100)...

This work presents the first atomic scale evidence for ferroelectric polarization inversion on unit cell level in a wurtzite-type material based epitaxial Al0.75Sc0.25N thin films. The electric field induced formation of Al-polar domains originally N-polar film is unambiguously determined by resolution imaging using aberration-corrected scanning transmission electron microscopy (STEM). Anisotropic etching supports STEM results confirming complete and homogenous at surface switched regions...

Through its dependence on low symmetry crystal phases, ferroelectricity is inherently a property tied to the lower temperature ranges of phase diagram for given material. This paper presents conclusive evidence that in case ferroelectric Al1−xScxN, has be seen as purely relative term, since ferroelectric-to-paraelectric transition confirmed surpass 1100 °C and thus virtually any other thin film ferroelectric. We arrived at this conclusion through investigating structural stability 0.4–2 μm...

Abstract The recent emergence of wurtzite‐type nitride ferroelectrics such as Al 1‐ x Sc N has paved the way for introduction all‐epitaxial, all‐wurtzite‐type ferroelectric III‐N semiconductor heterostructures. This paper presents first in‐depth structural and electrical characterization an epitaxial heterostructure by investigating sputter deposited solid solutions with between 0.19 0.28 grown over doped n‐GaN. results detailed investigations on strain state initial unit‐cell polarity...

Abstract Analog switching in ferroelectric devices promises neuromorphic computing with the highest energy efficiency if limited device scalability can be overcome. To contribute to a solution, one reports on characteristics of sub‐5 nm thin Al 0.74 Sc 0.26 N films grown Pt/Ti/SiO 2 /Si and epitaxial Pt/GaN/sapphire templates by sputter‐deposition. In this context, study focuses following major achievements compared previously available wurtzite‐type ferroelectrics: 1) Record low voltages...

The discovery of ferroelectricity in aluminum scandium nitride (Al1-xScxN) opens technological perspectives for harsh environments and space-related memory applications, considering the high-temperature stability piezoelectricity nitride. ferroelectric material properties 100 nm-thick Al0.72Sc0.28N are studied up to 873 K, combining both electrical situ X-ray diffraction measurements as well transmission electron microscopy energy-dispersive spectroscopy. present work demonstrates that can...

Abstract In this paper, using a combination of pulse testing measurements and piezoresponse force microscopy (PFM), an investigation the polarization reversal behavior accompanying resistive switching in Al 0.72 Sc 0.28 N thin film capacitors is reported. The obtained results reveal transition from nucleation‐limited (NLS) low field range toward more uniform described by Kolmogorov–Avrami–Ishibashi (KAI) model high range. It found that exhibit unusually steep change time– it decreases five...

The analog switching properties of wurtzite-type ferroelectrics hold unforeseen potential for future-generation electronic devices, such as neuromorphic memory concepts based on memristive devices. However, investigative studies expanding our detailed knowledge the physical ferroelectric domain walls and modulation large-scale patterns are still very limited. Up to date, exact atomic configuration electric field-induced has not been identified due its inclined wedge-shaped three-dimensional...

Scandium alloyed aluminum nitride (Al1−xScxN) thin films were fabricated by reactive pulsed direct current co-sputtering of separate scandium and targets with x ≤ 0.37. A significant improvement the clamped transversal piezoelectric response to strain e31,f from −1.28 C/m2 −3.01 was recorded, while dielectric constant loss angle remain low. Further, built-in stress level Al1−xScxN found be tuneable varying pressure, Ar/N2 ratio, Sc content. The thus resulting enhancement expectable signal...

MEMS sensors based on magnetoelectric composites have attracted great interest due to their capability detect weak magnetic fields, showing high potential in applications like biomagnetic field detection and particle imaging. This paper reports a scandium aluminum nitride thin film-based sensor. The sensor consists of polycrystalline silicon cantilever with size 1000 μm × 200 covered by piezoelectric Al0.73Sc0.27N magnetostrictive (Fe90Co10)78Si12B10 film. performance the presented is...

Thickness scaling of ferroelectricity in AlScN is a determining factor for its potential application neuromorphic computing and memory devices. In this letter, we report on ultrathin (10 nm) Al0.72Sc0.28N films that are ferroelectrically switchable at room temperature. All-epitaxial Al0.72Sc0.28N/Pt heterostructures grown by magnetron sputtering onto GaN/sapphire substrates followed an situ Pt capping approach to avoid oxidation the film surface. Structural characterization X-ray diffraction...

In this work, the value and polarity of spontaneous piezoelectric polarization have been investigated, as use two different reference structures for wurtzite-type group-III nitrides, namely, zinc-blende layered-hexagonal crystal lattice, resulted in predictions. It was found that although differences heterostructures such wurtzite Al1−xScxN/GaN lead to similar interface sheet charges, a significant mismatch is observed when reversal considered. The charge predicted before after Al1−xScxN...

Abstract Wurtzite‐structured ferroelectrics, such as aluminum scandium nitride (Al 1‐x Sc x N), are among the most promising candidates for implementing innovative nonvolatile memory concepts into commercial technologies. However, opposite state (OS) retention limits long‐term performances. Since verifying requirement directly up to 10 years, typically targeted by technologies, is timely unfeasible, developing a model predict 10‐year OS performances of wurtzite‐structured ferroelectrics...

We present an analytical and experimental study on low-noise piezoelectric thin film resonators that utilize the delta-E effect of a magnetostrictive layer to measure magnetic fields at low frequencies. Calculations from physical model electromechanical resonator enable electrode designs efficiently operate in first second transversal bending modes. As predicted by our calculations, adapted design improves sensitivity factor 6 reduces dynamic range sensor output 16 dB, which significantly...

This paper investigates wake-up and imprint in ferroelectric Al0.70Sc0.30N films. The study employs a series of electrical measurements with varying field amplitudes waveforms to understand the origin underlying principle as well their relation. It is shown that material can be considered free. However, inherent variation polarization-electric hysteresis combination minor loops result like effect. effect most likely related formation persistent inversion domain nuclei—a mechanism discussed...

The wurtzite structure is one of the most frequently found crystal structures in modern semiconductors and its inherent spontaneous polarization a defining materials property. Despite this significance, confusion has been rampant literature with respect to orientation inside unit cell structure, especially for technologically very relevant III-N compounds (AlN, GaN, InN). In particular, reported either point up or down same orientation, depending on source—with important implications for,...

Abstract The ongoing research on and development of increasingly intelligent artificial systems propels the need for bio inspired pressure sensitive spiking circuits. Here we present an adapting tactile sensor, based a neuronal model piezoelectric field-effect transistor (PiezoFET). sensor device consists metal-oxide semiconductor comprising aluminium-scandium-nitride (Al x Sc 1−x N) layer inside gate stack. so augmented is to mechanical stress. In combination with analogue circuit, this...

Ferroelectric thin films of wurtzite-type aluminum scandium nitride (Al1−xScxN) are promising candidates for non-volatile memory applications and high-temperature sensors due to their outstanding functional thermal stability exceeding most other ferroelectric film materials. In this work, the expansion along with temperature its interrelated effects have been investigated Al1−xScxN on sapphire Al2O3(0001) Sc concentrations x (x = 0, 0.09, 0.23, 0.32, 0.40) using in situ X-ray diffraction...

AlxSc1–xN is a nitride-ferroelectric compatible with both CMOS and GaN technology. The origin of ferroelectricity in these ternary nitrides relies on the full inversion nitrogen atom positions, which significantly different structural mechanism than conventional perovskites. Therefore, its ferroelectric characteristics exhibit high remanent polarization tunable coercive field but suffer heavily from leakage currents during switching event. In this article, we studied epitaxially grown...

This paper presents a piezoelectrically (AlScN) driven 3 × quasi-static mirror matrix, where each MEMS utilizes three-level-construction comprising plate (diameter = 0.8 mm), pillar and four AlScN actuators hidden beneath the plate, reducing chip size to 1.1 1.3 mm2. as high performance piezoelectric material is used deliver large force enabling mechanical tilting angle of ±14° at 150 VDC, in addition great linearity, repeatability long-term stability. For realizing 3D construction three...

In this work, we present a method for growing highly c-axis oriented aluminum scandium nitride (AlScN) thin films on (100) silicon (Si), dioxide (SiO2) and epitaxial polysilicon (poly-Si) substrates using substrate independent approach. The presented offers great advantages in applications such as piezoelectric thin-film-based surface acoustic wave devices where metallic seed layer cannot be used. approach relies AlN to establish wurtzite nucleation the growth of w-AlScN films. Both AlScN...

Magnetoelectric thin-film sensors based on the delta-E effect have widely been reported for detection of low frequency and small amplitude magnetic fields. Such are usually fabricated with microelectromechanical system technology, where aluminum nitride (AlN) is established piezoelectric material. Here, we present scandium (AlScN) instead compare it AlN using two identical design. The experimentally theoretically analyzed regarding sensitivity, noise, limit (LOD), resonator linearity. We...