Polycrystalline κ-Ga₂O₃ on Si(100) substrates with GZO buffer layers.

Area of Science:

• Materials Science
• Semiconductor Physics
• Thin Film Deposition

Background:

• Kappa-phase gallium oxide (κ-Ga₂O₃) is a promising piezoelectric semiconductor for radio-frequency devices.
• Heteroepitaxial growth on silicon is hindered by lattice mismatch and oxidation.
• Developing κ-Ga₂O₃ on silicon is crucial for advanced electronic applications.

Purpose of the Study:

• To demonstrate the growth of polycrystalline κ-Ga₂O₃ thin films on Si(100) substrates.
• To investigate the role of Ga-doped ZnO (GZO) buffer layers in enabling this growth.
• To characterize the structural properties and interfacial behavior of the deposited films.

Main Methods:

• Mist chemical vapor deposition (mist CVD) for κ-Ga₂O₃ film deposition.
• Utilizing Ga-doped ZnO (GZO) as a buffer layer on Si(100) substrates.
• Structural analysis using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM).

Main Results:

• Successfully grown polycrystalline κ-Ga₂O₃ thin films on Si(100) using GZO buffer layers.
• Films exhibit a c-axis oriented polycrystalline structure with isotropic properties.
• Identified a ZnGa₂O₄ intermediate layer crucial for phase stabilization at the κ-Ga₂O₃/GZO interface.

Conclusions:

• Polycrystalline κ-Ga₂O₃ films can be effectively grown on silicon substrates via mist CVD with GZO buffer layers.
• The identified ZnGa₂O₄ interlayer is key to stabilizing the desired κ-phase.
• This approach provides a viable pathway for fabricating κ-Ga₂O₃-based piezoelectric devices on silicon.