Ever since its invention in the 1980s, the compound semiconductor heterojunction-based high electron mobility transistor (HEMT) has been widely used in radio frequency (RF) applications. This book provides readers with broad coverage on techniques and new trends of HEMT, employing leading compound semiconductors, III-N and III-V materials. The content includes an overview of GaN HEMT device-scaling technologies and experimental research breakthroughs in fabricating various GaN MOSHEMT transistors. Readers are offered an inspiring example of monolithic integration of HEMT with LEDs, too....