Tuning composition in graded AlGaN channel HEMTs toward improved linearity for low-noise radio-frequency amplifiers
(2023) In Applied Physics Letters 122(15).- Abstract
Compositionally graded channel AlGaN/GaN high electron mobility transistors (HEMTs) offer a promising route to improve device linearity, which is necessary for low-noise radio-frequency amplifiers. In this work, we demonstrate different grading profiles of a 10-nm-thick AlxGa1-xN channel from x = 0 to x = 0.1 using hot-wall metal-organic chemical vapor deposition (MOCVD). The growth process is developed by optimizing the channel grading and the channel-to-barrier transition. For this purpose, the Al-profiles and the interface sharpness, as determined from scanning transmission electron microscopy combined with energy-dispersive x-ray spectroscopy, are correlated with specific MOCVD process parameters. The results are linked to the... (More)
Compositionally graded channel AlGaN/GaN high electron mobility transistors (HEMTs) offer a promising route to improve device linearity, which is necessary for low-noise radio-frequency amplifiers. In this work, we demonstrate different grading profiles of a 10-nm-thick AlxGa1-xN channel from x = 0 to x = 0.1 using hot-wall metal-organic chemical vapor deposition (MOCVD). The growth process is developed by optimizing the channel grading and the channel-to-barrier transition. For this purpose, the Al-profiles and the interface sharpness, as determined from scanning transmission electron microscopy combined with energy-dispersive x-ray spectroscopy, are correlated with specific MOCVD process parameters. The results are linked to the channel properties (electron density, electron mobility, and sheet resistance) obtained by contactless Hall and terahertz optical Hall effect measurements coupled with simulations from solving self-consistently Poisson and Schrödinger equations. The impact of incorporating a thin AlN interlayer between the graded channel and the barrier layer on the HEMT properties is investigated and discussed. The optimized graded channel HEMT structure is found to have similarly high electron density (∼9 × 10 12 cm-2) as the non-graded conventional structure, though the mobility drops from ∼ 2360 cm2/V s in the conventional to ∼ 960 cm2/V s in the graded structure. The transconductance gm of the linearly graded channel HEMTs is shown to be flatter with smaller g m ′ and g m ″ as compared to the conventional non-graded channel HEMT implying improved device linearity.
(Less)
- author
- organization
- publishing date
- 2023-04-10
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Applied Physics Letters
- volume
- 122
- issue
- 15
- article number
- 153501
- publisher
- American Institute of Physics (AIP)
- external identifiers
-
- scopus:85152923662
- ISSN
- 0003-6951
- DOI
- 10.1063/5.0141517
- language
- English
- LU publication?
- yes
- id
- 96b813c8-a0fc-4357-b00c-b0b6b9e1f019
- date added to LUP
- 2023-07-12 11:45:56
- date last changed
- 2023-11-08 07:27:15
@article{96b813c8-a0fc-4357-b00c-b0b6b9e1f019, abstract = {{<p>Compositionally graded channel AlGaN/GaN high electron mobility transistors (HEMTs) offer a promising route to improve device linearity, which is necessary for low-noise radio-frequency amplifiers. In this work, we demonstrate different grading profiles of a 10-nm-thick AlxGa1-xN channel from x = 0 to x = 0.1 using hot-wall metal-organic chemical vapor deposition (MOCVD). The growth process is developed by optimizing the channel grading and the channel-to-barrier transition. For this purpose, the Al-profiles and the interface sharpness, as determined from scanning transmission electron microscopy combined with energy-dispersive x-ray spectroscopy, are correlated with specific MOCVD process parameters. The results are linked to the channel properties (electron density, electron mobility, and sheet resistance) obtained by contactless Hall and terahertz optical Hall effect measurements coupled with simulations from solving self-consistently Poisson and Schrödinger equations. The impact of incorporating a thin AlN interlayer between the graded channel and the barrier layer on the HEMT properties is investigated and discussed. The optimized graded channel HEMT structure is found to have similarly high electron density (∼9 × 10 12 cm-2) as the non-graded conventional structure, though the mobility drops from ∼ 2360 cm2/V s in the conventional to ∼ 960 cm2/V s in the graded structure. The transconductance gm of the linearly graded channel HEMTs is shown to be flatter with smaller g m ′ and g m ″ as compared to the conventional non-graded channel HEMT implying improved device linearity.</p>}}, author = {{Papamichail, A. and Persson, A. R. and Richter, S. and Kühne, P. and Stanishev, V. and Persson, P. O.Å. and Ferrand-Drake Del Castillo, R. and Thorsell, M. and Hjelmgren, H. and Paskov, P. P. and Rorsman, N. and Darakchieva, V.}}, issn = {{0003-6951}}, language = {{eng}}, month = {{04}}, number = {{15}}, publisher = {{American Institute of Physics (AIP)}}, series = {{Applied Physics Letters}}, title = {{Tuning composition in graded AlGaN channel HEMTs toward improved linearity for low-noise radio-frequency amplifiers}}, url = {{http://dx.doi.org/10.1063/5.0141517}}, doi = {{10.1063/5.0141517}}, volume = {{122}}, year = {{2023}}, }