Entry Date:
January 24, 2019

Novel GaN Transistor Design for High Linearity Applications

Principal Investigator Tomas Palacios


Enhancing the linearity of Gallium Nitride (GaN) high-electron-mobility transistors (HEMTs) is essential for future RF applications that require extremely low intermodulation distortion and gain compression. In this project, we have studied the origins of non-linearities in GaN-based amplifiers and propose device-level solutions to improve linearity. First, the drop in transconductance (gm) at high current levels observed in GaN transistors can be mitigated with either self-aligned or finFET-like structures. This is due to the higher current-driving capability of the source access region on these devices. The second cause of device non-linearity has been linked to the large second derivative of the transconductance with respect to gate-source voltage (Vgs) (gm”). This can be overcome by using a new generation of engineered finFET transistors where the width of each fin is optimized for minimizing gm". In addition, the non-linear behavior of the device capacitances with operating voltage also plays a very important role in device non-linearities. In this case, too, nanostructures can be used to improve device performance. Finally, memory effects due to sur- face and buffer trap also contribute to non-linearities in amplifiers, and they can also be overcome through the use of nanostructures.