AlScN High Electron Mobility Transistors: Integrating High Piezoelectric, High K Dielectric, and Ferroelectric Functionality

This paper presents an overview of the promising physical properties of the aluminum scandium nitride (AlScN) ternary alloy system and its integration in radiofrequency heterostructure high electron mobility transistors (RF HEMTs). Specifically, heterostructures with AlScN demonstrate enhanced piezoelectric response and enhanced relative dielectric permittivity, as well as ferroelectric behavior. These promising physical phenomena are manifested in HEMTs that show larger on current densities compared to aluminum gallium nitride (AlGaN) HEMTs and display ferroelectric behavior. An overlook on future improvements in thin film deposition and device fabrication is discussed to fully maximize the potential devices and integrated circuits incorporating AlScN.