Advanced Characterization and Optimization of Epitaxial Growth Techniques for Wide-Bandgap Semiconductors: A Critical Analysis of GaN, SiC, AlGaN, Diamond, and Ga₂O₃ Synthesis Methods, Challenges, and Prospective Technological Innovations

Wide-bandgap (WBG) semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) play a critical role in advancing high-power and high-frequency electronic applications, including renewable energy, automotive, and telecommunications sectors. This paper provides an in-depth analysis of epitaxial growth techniques like Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), and Atomic Layer Epitaxy (ALE), each with unique benefits in defect control, crystal quality, and scalability. Low-energy approaches such as Hot-Filament Chemical Vapor Deposition (HFCVD) for SiC offer scalability and uniformity, addressing industrial requirements for cost-effective, high-purity substrates. The study explores advancements in AI-optimized epitaxy and hybrid growth techniques aimed at mitigating environmental impacts, such as recycling end-of-life WBG devices to minimize waste. The findings underscore the potential of these methods to drive the next generation of high-performance WBG devices and position ultrawide-bandgap (UWBG) materials like diamond and gallium oxide (Ga₂O₃) as frontrunners for extreme applications in power electronics and quantum devices.