A Comprehensive Overview of HEMT Structure and Fabrication Techniques

This paper presents a comprehensive overview of high electron mobility transistors (HEMTs), exploring the structural design and fabrication techniques that underpin their high-performance applications in power and high-frequency domains. The discussion begins with a detailed analysis of each HEMT layer, from the substrate to the encapsulation layers, explaining the role each plays in optimizing electron mobility, thermal management, and power efficiency. Various materials used in HEMTs, including AlGaN/GaN, AlGaAs/GaAs, InAlAs/InGaAs, and GaN-on-Si, are examined to highlight their distinct benefits and challenges in different operational contexts. Additionally, the paper outlines key fabrication processes like epitaxial growth, lithography, and metallization, which contribute to the HEMT's structural integrity and functional reliability. The insights provided aim to advance the understanding of HEMT architecture, paving the way for further innovation in electronic devices that require robust, efficient, and high-speed semiconductor technologies.