Journal Article

PUBDB-2025-04446

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Advancing the Growth of GaN on AlScN and AlYN by Metal–Organic Chemical Vapor Deposition

Streicher, I. (Corresponding author) ; Wolff, N.Extern* ; Duarte, T. ; Rehm, O.Extern* ; Straňák, P. ; Kirste, L. ; Prescher, M. ; Guo, X. ; Nicolosi, V. ; Baumgarten, L.Extern* ; Mueller, M.Extern*XFEL.EU* ; Kienle, L.Extern* ; Leone, S. (Corresponding author)

2025
Wiley-VCH GmbH Weinheim

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Please use a persistent id in citations: doi:10.1002/apxr.202500035  doi:10.3204/PUBDB-2025-04446

Abstract: High electron mobility transistors (HEMT) based on Al1-xScxN/GaN and Al1-xYxN/GaN heterostructures promise increased device performance and reliability due to the high sheet charge carrier density and the possibility to grow strain-free layers on GaN. Metal–organic chemical vapor deposition (MOCVD) offers high throughput, high structural quality, and good electrical characteristics. The growth of GaN layers on Al1-xScxN and Al1-xYxN is challenging, but at the same time crucial as passivation or for multichannel structures. GaN is observed to grow three-dimensionally on these nitrides, exposing not-passivated areas to surface oxidation. In this work, growth of 2–20 nm-thick, two-dimensional GaN layers is demonstrated. Optimization of growth conditions is enabled by understanding island formation on the atomic scale by aberration corrected scanning transmission electron microscopy (STEM) and hard X-ray photoelectron spectroscopy (HAXPES). Increased growth temperature, an AlN interlayer, low supersaturation conditions and the carrier gas are found to be key to enhance Ga adatom mobility. Growth of single crystalline GaN layers on Al1-xScxN and Al1-xYxN is unlocked and prevents oxidation of the underlying layers. Few nanometer thick GaN caps allow for depositing the gate metallization directly on the cap, whereas thicker ones allow for the growth of heterostructures for normally-off devices and multichannel structures.

Note: N.W. acknowledges funding from the Deutsche Forschungsgemeinschaft (DFG) under the framework of the collaborative research center “CRC1261” and KiNSIS for funding an external research visit.

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Contributing Institute(s):

1. DOOR-User (DOOR ; HAS-User)

Research Program(s):

1. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)
2. FS-Proposal: I-20230416 (I-20230416) (I-20230416)

Experiment(s):

1. PETRA Beamline P22 (PETRA III)

Appears in the scientific report 2025

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