Pulsed E-/D-Mode Switchable GaN HEMTs With a Ferroelectric AlScN Gate Dielectric

Yang, Jeong Yong; Oh, Seung‐Yoon; Yeom, Min Jae; Kim, Seokgi; Lee, G. W.; Kim, Sungkyu; Yoo, Geonwook

doi:10.1109/led.2023.3287913

Cited by 10 publications

(2 citation statements)

References 27 publications

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“…6,15 Knowing the correct polarity of the polarizations is very important for modeling polarization reversal in GaN-based heterostructures, such as ferroelectric high electron mobility transistors (FeHEMTs). [19][20][21][22] This is due to the fact that different polarities can result in the prediction of different signs of the interface sheet charges and, in consequence, in the sign of accumulated charge carriers that form the channel of the transistor.…”

Section: Modeling Of Polarization Reversal-induced Interface Sheet Ch...mentioning

confidence: 99%

Modeling of polarization reversal-induced interface sheet charge in wurtzite-type AlScN/GaN heterostructures

Yassine,

Nair

et al. 2024

Journal of Applied Physics

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In this work, the value and the polarity of the spontaneous and piezoelectric polarization have been investigated, as the use of two different reference structures for wurtzite-type group-III nitrides, namely, the zinc-blende and the layered-hexagonal crystal lattice, have resulted in different predictions. It was found that although the differences in value and polarity of the polarization for heterostructures such as wurtzite Al1−xScxN/GaN lead to similar interface sheet charges, a significant mismatch is observed when polarization reversal is considered. The interface sheet charge predicted before and after the polarization reversal in the wurtzite Al1−xScxN layer on GaN using the zinc-blende lattice as a reference predominantly shows a change in sign. When using the layered-hexagonal lattice as a reference, not only is the same polarity of the interface sheet charge maintained after polarization reversal, but it is even 30 times larger. In this case, the giant and positive spontaneous polarization values for metal-polar Al1−xScxN extracted from the ferroelectric switching, as well as the alignment of the piezoelectric polarization to it, were observed to be consistent with the predictions referenced to the layered-hexagonal lattice. Thus, it is concluded that the layered-hexagonal reference is not only more suitable for predicting the ferroelectric properties of wurtzite Al1−xScxN but should also be the correct reference when considering polarization reversal in heterostructures. If the significant increase in the interface sheet charge after polarization reversal is experimentally detected, it will allow the design and fabrication of novel devices for future high-frequency and power electronics applications.

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Section: Modeling Of Polarization Reversal-induced Interface Sheet Ch...mentioning

confidence: 99%

Modeling of polarization reversal-induced interface sheet charge in wurtzite-type AlScN/GaN heterostructures

Yassine,

Nair

et al. 2024

Journal of Applied Physics

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“…[8][9][10][11] In particular, Al 1−x Sc x N is an ideal fit for the integration of ferroelectrics into gallium nitride-based high electron mobility transistors. [12,13] The successful integration of Al 1−x Sc x N in the gate stack of field-effect transistors with two-dimensional channel materials, and into analog synaptic memristors was also demonstrated. [9,14,15] Nonetheless, realizing the full potential of Al 1−x Sc x N requires a comprehensive understanding of the mechanism of polarization reversal and domain structure dynamics involved in the ferroelectric switching process.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of N‐ to M‐Polar Switching in Ferroelectric Al_1−xSc_xN Capacitors

Guido,

Lu,

Lomenzo

et al. 2024

Advanced Science

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Ferroelectric wurtzite‐type aluminum scandium nitride (Al1−xScxN) presents unique properties that can enhance the performance of non‐volatile memory technologies. The realization of the full potential of Al1−xScxN requires a comprehensive understanding of the mechanism of polarization reversal and domain structure dynamics involved in the ferroelectric switching process. In this work, transient current integration measurements performed by a pulse switching method are combined with domain imaging by piezoresponse force microscopy (PFM) to investigate the kinetics of domain nucleation and wall motion during polarization reversal in Al0.85Sc0.15N capacitors. In the studied electric field range (from 4.4 to 5.6 MV cm−1), ferroelectric switching proceeds via domain nucleation and wall movement. The currently available phenomenological models are shown to not fully capture all the details of the complex dynamics of polarization reversal in Al0.85Sc0.15N. PFM reveals a non‐linear increase of both domain nucleation rate and lateral wall velocity during the switching process, as well as the dependency of the domain pattern on the polarization reversal direction. A continuously faster N‐ to M‐polar switching upon cycling is reported and ascribed to an increasing number of M‐polar nucleation sites and density of domain walls.

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Physics of Ferroelectric Wurtzite Al_1−xSc_xN Thin Films

Yang

2024

Adv Elect Materials

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Al1−xScxN emerges as a revolutionary ferroelectric material within the III‐N family. It combines exceptional switchable polarization (80–165 µC cm−2), highly tunable coercive fields (1.5–6.5 MV cm−¹), and a wide bandgap (4.9–5.6 eV). Unlike conventional ferroelectrics, Al1−xScxN exhibits remarkable compatibility with both CMOS and III‐N technologies. It can be fabricated on plastic substrates at low temperatures, demonstrating excellent flexibility and biocompatibility. Remarkably, Al1−xScxN maintains superior performance in harsh environments due to its outstanding thermal stability (up to 1100 °C). These unique characteristics position Al1−xScxN as a highly promising candidate for a wide range of applications, including high‐performance memory, in‐memory computing, neuromorphic computing, and next‐generation wearable and implantable devices, particularly for operation in complex environments. Despite its potential, Al1−xScxN faces challenges such as high coercive fields, significant leakage currents, and limited polarization reversal cycle life. Addressing these challenges require a deeper understanding of the fundamental physics controlling Al1−xScxN films. This review explores the origins of Al1−xScxN's ferroelectricity and phase stability, delves into the fundamental theory of wurtzite ferroelectricity, investigates mechanisms for controlling spontaneous polarization and coercive fields, examines recent research progress in Al1−xScxN ferroelectric devices, and outlines future development directions for this exciting material.

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Pulsed E-/D-Mode Switchable GaN HEMTs With a Ferroelectric AlScN Gate Dielectric

Cited by 10 publications

References 27 publications

Modeling of polarization reversal-induced interface sheet charge in wurtzite-type AlScN/GaN heterostructures

Modeling of polarization reversal-induced interface sheet charge in wurtzite-type AlScN/GaN heterostructures

Kinetics of N‐ to M‐Polar Switching in Ferroelectric Al_1−xSc_xN Capacitors

Physics of Ferroelectric Wurtzite Al_1−xSc_xN Thin Films

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Pulsed E-/D-Mode Switchable GaN HEMTs With a Ferroelectric AlScN Gate Dielectric

Cited by 10 publications

References 27 publications

Modeling of polarization reversal-induced interface sheet charge in wurtzite-type AlScN/GaN heterostructures

Modeling of polarization reversal-induced interface sheet charge in wurtzite-type AlScN/GaN heterostructures

Kinetics of N‐ to M‐Polar Switching in Ferroelectric Al1−xScxN Capacitors

Physics of Ferroelectric Wurtzite Al1−xScxN Thin Films

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Product

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Kinetics of N‐ to M‐Polar Switching in Ferroelectric Al_1−xSc_xN Capacitors

Physics of Ferroelectric Wurtzite Al_1−xSc_xN Thin Films