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

• Published in: arXiv.org 2023-02
• Main Authors: Casamento, J, Nomoto, K, Nguyen, T S, Lee, H, Savant, C, L Li, Hickman, A, Maeda, T, Encomendero, J, Gund, V, Lal, A, Hwang, J C M, Xing, H G, Jena, D
• Format: Article
• Language: English
• Subjects: Digital electronics; Electronics; Epitaxial growth; Ferroelectric materials; Ferroelectricity; Gallium nitrides; Hysteresis; Lattice matching; Semiconductor devices; Substrates; Transistors
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2302.14209

We report the first observation of ferroelectric gating in AlScN barrier wide-bandgap nitride transistors. These FerroHEMT devices realized by direct epitaxial growth represent a new class of ferroelectric transistors in which the semiconductor is itself polar, and the crystalline ferroelectric barrier is lattice-matched to the substrate. The FerroHEMTs reported here use the thinnest nitride high K and ferroelectric barriers to date to deliver the highest on currents at 4 A/mm, and highest speed AlScN transistors with fmax larger than 150 GHz observed in any ferroelectric transistor. The FerroHEMTs exhibit hysteretic Id Vgs loops with subthreshold slopes below the Boltzmann limit. A control AlN barrier HEMT exhibits neither hysteretic, nor sub Boltzmann behavior. While these results introduce the first epitaxial high K and ferroelectric barrier technology to RF and mm wave electronics, they are also of interest as a new material platform for combining memory and logic functionalities in digital electronics.