Innovative remote plasma source for atomic layer deposition for GaN devices

Knoops, H. C. M., Arts, K., Buiter, J. W., Martini, L. M., Engeln, R., Hemakumara, D. T., Powell, M., Kessels, W. M. M. (E.), Hodson, C. J. and O’Mahony, A. (2021) Innovative remote plasma source for atomic layer deposition for GaN devices. Journal of Vacuum Science and Technology A: Vacuum, Surfaces, and Films, 39(6), 062403. (doi: 10.1116/6.0001318)

Abstract

High-quality dielectric films could enable GaN normally off high-electron-mobility transistors (HEMTs). Plasma atomic layer deposition (ALD) is known to allow for controlled high-quality thin-film deposition, and in order to not exceed energy and flux levels leading to device damage, the plasma used should preferably be remote for many applications. This article outlines ion energy flux distribution functions and flux levels for a new remote plasma ALD system, Oxford Instruments Atomfab™, which includes an innovative, RF-driven, remote plasma source. The source design is optimized for ALD for GaN HEMTs for substrates up to 200 mm in diameter and allows for Al2O3 ALD cycles of less than 1 s. Modest ion energies of <50 eV and very low ion flux levels of <1013 cm−2 s−1 were found at low-damage conditions. The ion flux can be increased to the high 1014 cm−2 s−1 range if desired for other applications. Using low-damage conditions, fast ALD saturation behavior and good uniformity were demonstrated for Al2O3. For films of 20 nm thickness, a breakdown voltage value of 8.9 MV/cm was obtained and the Al2O3 films were demonstrated to be suitable for GaN HEMT devices where the combination with plasma pretreatment and postdeposition anneals resulted in the best device parameters.

• Item Type: Articles
• Keywords: Surfaces, coatings and films, surfaces and interfaces, condensed matter physics.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hemakumara, Miss Dilini
• Authors: Knoops, H. C. M., Arts, K., Buiter, J. W., Martini, L. M., Engeln, R., Hemakumara, D. T., Powell, M., Kessels, W. M. M. (E.), Hodson, C. J., and O’Mahony, A.
• College/School: College of Science and Engineering > School of Engineering
• Journal Name: Journal of Vacuum Science and Technology A: Vacuum, Surfaces, and Films
• Publisher: AIP Publishing
• ISSN: 0734-2101
• ISSN (Online): 1520-8559
• Copyright Holders: Copyright © 2021 The Authors
• First Published: First published in Journal of Vacuum Science and Technology A: Vacuum, Surfaces, and Films 39(6):062403
• Publisher Policy: Reproduced under a Creative Commons licence