Influence of Oxygen on β-Ga₂O₃ Films Deposited on Sapphire Substrates by MOCVD

Abstract

In this paper, β-Ga 2 O 3 films were deposited on c-plane sapphire substrates by metal-organic chemical vapor deposition. The impact of oxygen flow rate on crystalline quality, surface morphology, optical transmittance, and growth rate were systematically investigated. X-ray diffraction revealed that β-Ga 2 O 3 films preferentially grew along (−201) crystal plane family when grown on sapphire substrates, and the full-width at half maximum indicated that the crystal quality of β-Ga 2 O 3 film was improved by increasing the oxygen flow rate. The oxygen flow rate greatly influenced the surface morphology and growth rate, and the optical band gaps of β-Ga 2 O 3

Heterogrowth of β-(AlxGa1–x)2O3 Thin Films on Sapphire Substrates

“…By comparing the research of Po-Wei Chen et al, our results were consistent with their reports. If we calibrated the previous results of β-Ga 2 O 3 films, it can be clearly observed in Figure b–d that the β-(Al x Ga 1– x ) 2 O 3 diffraction peaks gradually shifted to larger diffraction angles with the increase of the TMAl flow rate, which can be attributed to more Al atoms being incorporated into the crystal lattice . According to eq …”

“…Therefore, the surface undulation of the β-(Al x Ga 1– x ) 2 O 3 films was indeed worse compared to that of the film without Al doping. In fact, in our previous research, the MO/O 2 flow rate ratio would effectively influence the surface undulations. Therefore, the Al atoms would increase the surface RMS roughness.…”

Influence of Oxygen on Ga2O3 Deposition at Low Temperature by MOCVD

“…The reduced grain size and dense distribution lead to a slightly reduced film thickness and a smoother surface, which reduces the extent of surface fluctuations. , Besides, the growth mode of the film is significantly influenced by the O/Ga ratio. A lower or higher O/Ga ratio is found to promote a three-dimensional growth mode, leading to increased surface fluctuation. , …”

“…A lower or higher O/Ga ratio is found to promote a three-dimensional growth mode, leading to increased surface fluctuation. 29,30 The cross-sectional SEM image of the Ga 2 O 3 film is depicted in Figure 2, and the mean thicknesses of the films deposited at the oxygen flow rate of 1400, 1600, 1800, and 2100 sccm are about 285.3, 257.6, 243.2, and 254.2 nm, respectively. The film's growth rate can be calculated as approximately 4.76, 4.29, 4.05, and 4.24 nm/min, respectively, corresponding to the incremental rise in oxygen flow rate.…”