Synthesis of wide bandgap Ga₂O₃(E_g ∼ 4.6-4.7 eV) thin films on sapphire by low pressure chemical vapor deposition

Abstract

This paper presents the synthesis of wide bandgap Ga2O3 thin films on differently oriented sapphire substrates by using low pressure chemical vapor deposition (LPCVD) technique. The effects of substrate orientation on the Ga2O3 thin film surface morphology, crystal orientation, growth rate, and optical properties were studied. The Ga2O3 thin films were synthesized on the c‐plane (0001), a‐plane (11−20), and r‐plane (1−102) sapphire substrates using high purity metallic Ga and oxygen (O2) as source materials and argon (Ar) as carrier gas. The Ga2O3 thin films grown on the c‐plane and a‐plane sapphire substrates are composed of pure β‐Ga2O3. A mixture of β‐Ga2O3 and α‐Ga2O3 phases is observed for the films grown on r‐plane sapphire substrate. Well‐distinct transmission, absorption, and reflectance edge at Eg ∼ 4.6–4.7 eV are visible for all the films in the optical spectra measured in the spectral range from 200 to 800 nm.

Heteroepitaxy of N-type β-Ga2O3 thin films on sapphire substrate by low pressure chemical vapor deposition

“…[10][11][12][13][14][15] While the traditional molecular beam epitaxy (MBE) growth method can produce high quality Ga 2 O 3 materials, the challenge of slow growth rates still need to be addressed. 11,12 Among the limited efforts towards heteroepitaxy of b-Ga 2 O 3 thin films on foreign substrates, [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] none has reported heteroepitaxial Ga 2 O 3 films with good electrical properties.…”

“…Previously, we have demonstrated the feasibility to synthesize b-Ga 2 O 3 on sapphire substrates via low pressure chemical vapor deposition (LPCVD), 26 as well as the LPCVD synthesis of high quality b-Ga 2 O 3 homoepitaxial films on (010) b-Ga 2 O 3 substrates. 33 In addition, we also demonstrated the synthesis of b-Ga 2 O 3 rod structures on 3C-SiC-on-Si substrates via LPCVD.…”

Density Functional Theory Simulations of Water Adsorption and Activation on the (−201) β‐Ga2O3 Surface

“…For example, various experiments indicate that (−201) is the preferred growth direction for thin films grown on c‐plane sapphire . This orientation can be related to the fact that the oxygen atoms of the (001) plane of the sapphire substrate have a similar atomic arrangement compared to the (−201) plane of β‐Ga 2 O 3 ,. Interestingly, the XRD pattern of catalytically grown Zn‐doped p‐type β‐Ga 2 O 3 nanowires shows a significant peak at (−201) .…”

Towards High‐Mobility Heteroepitaxial β‐Ga2O3 on Sapphire − Dependence on The Substrate Off‐Axis Angle

“…Several epitaxial growth techniques for β‐Ga 2 O 3 thin films such as molecular beam epitaxy (MBE), metal organic vapor phase epitaxy (MOVPE), halide vapor phase epitaxy (HVPE), and low pressure chemical vapor deposition (LPCVD) have been reported recently. The current efforts focus on β‐Ga 2 O 3 homoepitaxial growth on native substrates as it is expected to produce high quality materials for device applications .…”