High crystalline quality homoepitaxial Si-doped β-Ga2O3(010) layers with reduced structural anisotropy grown by hot-wall MOCVD
Gogova, D. ; Tran, D. Q. ; Stanishev, V. ; Jokubavicius, V. ; Vines, L. ; Schubert, M. LU
; Yakimova, R.
; Paskov, P. P.
and Darakchieva, V.
LU
(2024)
In Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
42(2).
- Abstract
A new growth approach, based on the hot-wall metalorganic chemical vapor deposition concept, is developed for high-quality homoepitaxial growth of Si-doped single-crystalline β -Ga 2 O 3 layers on (010)-oriented native substrates. Substrate annealing in argon atmosphere for 1 min at temperatures below 600 ° C is proposed for the formation of epi-ready surfaces as a cost-effective alternative to the traditionally employed annealing process in oxygen-containing atmosphere with a time duration of 1 h at about 1000 ° C. It is shown that the on-axis rocking curve widths exhibit anisotropic dependence on the azimuth angle with minima for in-plane direction parallel to the [001] and maximum for the [100] for both substrate and layer. The... (More)
A new growth approach, based on the hot-wall metalorganic chemical vapor deposition concept, is developed for high-quality homoepitaxial growth of Si-doped single-crystalline β -Ga 2 O 3 layers on (010)-oriented native substrates. Substrate annealing in argon atmosphere for 1 min at temperatures below 600 ° C is proposed for the formation of epi-ready surfaces as a cost-effective alternative to the traditionally employed annealing process in oxygen-containing atmosphere with a time duration of 1 h at about 1000 ° C. It is shown that the on-axis rocking curve widths exhibit anisotropic dependence on the azimuth angle with minima for in-plane direction parallel to the [001] and maximum for the [100] for both substrate and layer. The homoepitaxial layers are demonstrated to have excellent structural properties with a β -Ga 2 O 3 (020) rocking curve full-widths at half-maximum as low as 11 arc sec, which is lower than the corresponding one for the substrates (19 arc sec), even for highly Si-doped (low 10 19 cm − 3 range) layers. Furthermore, the structural anisotropy in the layer is substantially reduced with respect to the substrate. Very smooth surface morphology of the epilayers with a root mean square roughness value of 0.6 nm over a 5 × 5 μ m 2 area is achieved along with a high electron mobility of 69 cm 2 V − 1 s − 1 at a free carrier concentration n = 1.9 × 10 19 cm − 3 . These values compare well with state-of-the-art parameters reported in the literature for β -Ga 2 O 3 (010) homoepitaxial layers with respective Si doping levels. Thermal conductivity of 17.4 W m − 1 K − 1 is determined along the [010] direction for the homoepitaxial layers at 300 K, which approaches the respective value of bulk crystal (20.6 W m − 1 K − 1 ). This result is explained by a weak boundary effect and a low dislocation density in the homoepitaxial layers.
(Less)
- author
- Gogova, D.
; Tran, D. Q.
; Stanishev, V.
; Jokubavicius, V.
; Vines, L.
; Schubert, M.
LU
; Yakimova, R.
; Paskov, P. P.
and Darakchieva, V.
LU
- organization
- publishing date
- 2024-03-01
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
- volume
- 42
- issue
- 2
- article number
- 022708
- publisher
- American Institute of Physics (AIP)
- external identifiers
-
- scopus:85186464728
- ISSN
- 0734-2101
- DOI
- 10.1116/6.0003424
- language
- English
- LU publication?
- yes
- id
- 077e653f-738d-442d-b89f-ba86981ab5b3
- date added to LUP
- 2024-03-15 14:47:07
- date last changed
- 2024-03-18 08:01:51
@article{077e653f-738d-442d-b89f-ba86981ab5b3,
abstract = {{<p>A new growth approach, based on the hot-wall metalorganic chemical vapor deposition concept, is developed for high-quality homoepitaxial growth of Si-doped single-crystalline β -Ga 2 O 3 layers on (010)-oriented native substrates. Substrate annealing in argon atmosphere for 1 min at temperatures below 600 ° C is proposed for the formation of epi-ready surfaces as a cost-effective alternative to the traditionally employed annealing process in oxygen-containing atmosphere with a time duration of 1 h at about 1000 ° C. It is shown that the on-axis rocking curve widths exhibit anisotropic dependence on the azimuth angle with minima for in-plane direction parallel to the [001] and maximum for the [100] for both substrate and layer. The homoepitaxial layers are demonstrated to have excellent structural properties with a β -Ga 2 O 3 (020) rocking curve full-widths at half-maximum as low as 11 arc sec, which is lower than the corresponding one for the substrates (19 arc sec), even for highly Si-doped (low 10 19 cm − 3 range) layers. Furthermore, the structural anisotropy in the layer is substantially reduced with respect to the substrate. Very smooth surface morphology of the epilayers with a root mean square roughness value of 0.6 nm over a 5 × 5 μ m 2 area is achieved along with a high electron mobility of 69 cm 2 V − 1 s − 1 at a free carrier concentration n = 1.9 × 10 19 cm − 3 . These values compare well with state-of-the-art parameters reported in the literature for β -Ga 2 O 3 (010) homoepitaxial layers with respective Si doping levels. Thermal conductivity of 17.4 W m − 1 K − 1 is determined along the [010] direction for the homoepitaxial layers at 300 K, which approaches the respective value of bulk crystal (20.6 W m − 1 K − 1 ). This result is explained by a weak boundary effect and a low dislocation density in the homoepitaxial layers.</p>}},
author = {{Gogova, D. and Tran, D. Q. and Stanishev, V. and Jokubavicius, V. and Vines, L. and Schubert, M. and Yakimova, R. and Paskov, P. P. and Darakchieva, V.}},
issn = {{0734-2101}},
language = {{eng}},
month = {{03}},
number = {{2}},
publisher = {{American Institute of Physics (AIP)}},
series = {{Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films}},
title = {{High crystalline quality homoepitaxial Si-doped β-Ga<sub>2</sub>O<sub>3</sub>(010) layers with reduced structural anisotropy grown by hot-wall MOCVD}},
url = {{http://dx.doi.org/10.1116/6.0003424}},
doi = {{10.1116/6.0003424}},
volume = {{42}},
year = {{2024}},
}