Annealing induced phase transition and optical properties of Ga2O3 thin films synthesized by sputtering technique

Meng, Yijin; Gao, Yuqi; Chen, Keyu; Lu, Jixue; Xian, Fenglin; Xu, Linhua; Zheng, Gaige; Kuang, Wenjian; Cao, Zhaolou

doi:10.1016/j.ijleo.2021.167515

Cited by 18 publications

(22 citation statements)

References 35 publications

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“…[ 21,22 ] Extensive studies of the thermal annealing effects on phase transformation in Ga 2 O 3 grown using various deposition processes on sapphire and 4H‐SiC substrates have been performed. Thermal annealing of Ga 2 O 3 causes an incomplete phase transformation, [ 23 ] mixed phases, [ 24 ] mixed planes of β‐phase, [ 25 ] thin films cracking, [ 26 ] and atomic diffusion from substrates as discussed in the supporting information. As a result, thermal annealing is not a suitable option for achieving phase pure β‐Ga 2 O 3 grown on hexagonal materials.…”

Section: Introductionmentioning

confidence: 99%

Phase Stabilized MOCVD Growth of β‐Ga₂O₃ Using SiO_x on c‐Plane Sapphire and AlN/Sapphire Template

Jewel

Hasan

Crittenden

et al. 2023

Physica Status Solidi (a)

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The growth of monoclinic phase-pure gallium oxide (β-Ga 2 O 3 ) layers by metalorganic chemical vapor deposition on c-plane sapphire and aluminum nitride (AlN) templates using silicon-oxygen bonding (SiO x ) as a phase stabilizer is reported. The β-Ga 2 O 3 layers are grown using triethylgallium, oxygen, and silane for gallium, oxygen, and silicon precursors, respectively, at 700 °C, with and without silane flow in the process. The samples grown on sapphire with SiO x phase stabilization show a notable change from samples without phase stabilization in the roughness and resistivity, from 16.2 to 4.2 nm and from 85.82 to 135.64 Ω cm, respectively. X-ray diffraction reveals a pure-monoclinic phase, and Raman spatial mapping exhibits higher tensile strain in the films in the presence of SiO x . The β-Ga 2 O 3 layers grown on an AlN template, using the same processes as for sapphire, show an excellent epitaxial relationship between β-Ga 2 O 3 and AlN and have a significant change in β-Ga 2 O 3 surface morphology.

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Section: Introductionmentioning

confidence: 99%

Phase Stabilized MOCVD Growth of β‐Ga₂O₃ Using SiO_x on c‐Plane Sapphire and AlN/Sapphire Template

Jewel

Hasan

Crittenden

et al. 2023

Physica Status Solidi (a)

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“…Ga 2 O 3 is known to have at least six polymorphs, α-, β-, γ-, δ-, ε-, and κ-Ga 2 O 3 . , β-Ga 2 O 3 is the most stable phase of those. However, the possibilities to obtain thin films containing other phases that are energetically less favorable are also of marked interest.…”

Section: Introductionmentioning

confidence: 99%

“…Possibilities to improve high-performance power-electronic devices used in trains, charging infrastructure of electrical cars, grid-scale energy storage, motor controls, and different military systems are constantly studied. Owing to its wide bandgap and large breakdown field, gallium oxide (Ga 2 O 3 ) could be a promising material for these applications. − Moreover, Ga 2 O 3 is a prospective material for gas sensors, , solar-blind UV detectors, X-ray detectors, and solar cells. − , …”

Section: Introductionmentioning

confidence: 99%

“…Gallium oxide thin films have been prepared by various methods, including magnetron sputtering, , pulsed laser deposition, , chemical vapor deposition, ,,, and atomic layer deposition (ALD) . Among these methods, ALD provides excellent conformity, thickness control, and reproducibility at a nanometer level, which makes this technique most suitable for many applications …”

Section: Introductionmentioning

confidence: 99%

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Atomic Layer Deposition of Ga₂O₃ from GaI₃ and O₃: Growth of High-Density Phases

Aarik

Mändar

Kozlova

et al. 2023

Crystal Growth & Design

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Gallium oxide thin films, containing either α-Ga2O3 or κ-Ga2O3 crystalline phases, were grown by atomic layer deposition (ALD) by using GaI3 and O3 as precursors. The κ-Ga2O3 phase was observed in the films grown on Si(1 0 0) at substrate temperatures ≥450 °C, while α-Ga2O3 was obtained at temperatures ≥275 °C on α-Cr2O3 seed layers deposited on Si(1 0 0). The seed layers with thicknesses down to 0.7 nm appeared to be sufficient to initiate the α-Ga2O3 growth. The densities of 5.2–5.3 g/cm3 for amorphous films deposited at the substrate temperatures 150–234 °C, 5.9−6.1 g/cm3 for the films deposited on uncoated Si substrates at 450–550 °C, and 6.3−6.4 g/cm3 for the films deposited on α-Cr2O3 seed layers at 350–550 °C were determined from X-ray reflectometry measurements. The growth per cycle decreased from 0.17 to 0.05–0.09 nm with the growth temperature increase from 150 to 550 °C. Notably, the growth rates of α-Ga2O3 films on α-Cr2O3 seed layers were significantly higher at 350–450 °C than those of the films deposited on uncoated Si at the same temperatures, indicating that crystal structure influenced the growth per cycle in this ALD process. The concentration of iodine impurities did not exceed 3.2 at. % in the films deposited at 150 °C. With the growth-temperature increase to 350 °C, the concentration of impurities decreased to ≤0.04 at. % in the films grown on bare Si and ≤0.01 at. % in the films grown on α-Cr2O3 seed layers.

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“…Here, the β-Ga 2 O 3 films were fabricated and characterized by post-annealing with a rapid thermal annealing (RTA) system at various temperatures after deposition onto c-plane sapphire substrates by RF magnetron sputtering at room temperature to enhance the crystalline quality. There have been several previous investigations on the effects of the post-annealing process of sputter-deposited Ga 2 O 3 films [2,19,20], but there have been few studies to apply these films as a lattice template on the c-sapphire substrate for application to power devices, except for optical devices. For the fabrication of the β-Ga 2 O 3 buffer layer at high temperatures, the residual stress of the β-Ga 2 O 3 films should be studied intensively as a function of the temperature.…”

Section: Introductionmentioning

confidence: 99%

Magnetron Sputter-Deposited β-Ga2O3 Films on c-Sapphire Substrate: Effect of Rapid Thermal Annealing Temperature on Crystalline Quality

Pech

Kim

2022

Coatings

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Gallium oxide (Ga2O3) is a semiconductor with a wide bandgap of ~5.0 eV and large breakdown voltages (>8 MV·cm−1). Among the crystal phases of Ga2O3, the monoclinic β-Ga2O3 is well known to be suitable for many device applications because of its chemical and thermal stability. The crystalline quality of polycrystalline β-Ga2O3 films on c-plane sapphire substrates was studied by rapid thermal annealing (RTA) following magnetron sputtering deposition at room temperature. Polycrystalline β-Ga2O3 films are relatively simple to prepare; however, their crystalline quality needs enhancement. The β-phase was achieved at 900 °C with a crystallite size and d-spacing of 26.02 and 0.2350 nm, respectively, when a mixture of ε- and β-phases was observed at temperatures up to 800 °C. The strain was released in the annealed Ga2O3 films at 900 °C; however, the clear and uniform orientation was not perfect because of the increased oxygen vacancy in the film at that temperature. The improved polycrystalline β-Ga2O3 films with dominant (−402)-oriented crystals were obtained at 900 °C for 45 min under a N2 gas atmosphere.

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Annealing induced phase transition and optical properties of Ga2O3 thin films synthesized by sputtering technique

Cited by 18 publications

References 35 publications

Phase Stabilized MOCVD Growth of β‐Ga₂O₃ Using SiO_x on c‐Plane Sapphire and AlN/Sapphire Template

Phase Stabilized MOCVD Growth of β‐Ga₂O₃ Using SiO_x on c‐Plane Sapphire and AlN/Sapphire Template

Atomic Layer Deposition of Ga₂O₃ from GaI₃ and O₃: Growth of High-Density Phases

Magnetron Sputter-Deposited β-Ga2O3 Films on c-Sapphire Substrate: Effect of Rapid Thermal Annealing Temperature on Crystalline Quality

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Annealing induced phase transition and optical properties of Ga2O3 thin films synthesized by sputtering technique

Cited by 18 publications

References 35 publications

Phase Stabilized MOCVD Growth of β‐Ga2O3 Using SiOx on c‐Plane Sapphire and AlN/Sapphire Template

Phase Stabilized MOCVD Growth of β‐Ga2O3 Using SiOx on c‐Plane Sapphire and AlN/Sapphire Template

Atomic Layer Deposition of Ga2O3 from GaI3 and O3: Growth of High-Density Phases

Magnetron Sputter-Deposited β-Ga2O3 Films on c-Sapphire Substrate: Effect of Rapid Thermal Annealing Temperature on Crystalline Quality

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Product

Resources

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Phase Stabilized MOCVD Growth of β‐Ga₂O₃ Using SiO_x on c‐Plane Sapphire and AlN/Sapphire Template

Phase Stabilized MOCVD Growth of β‐Ga₂O₃ Using SiO_x on c‐Plane Sapphire and AlN/Sapphire Template

Atomic Layer Deposition of Ga₂O₃ from GaI₃ and O₃: Growth of High-Density Phases