A scalable electrothermal model using a three‐dimensional thermal analysis model forGaN‐on‐diamondhigh‐electron‐mobility transistors

Abstract

AbstractA scalable eletrothermal model is necessary for a high‐power amplifier design for accurate accounting of thermal effects. Toward this end, this study presents a scalable large‐signal model of gallium‐nitride (GaN) high‐electron‐mobility transistors (HEMTs) on diamond substrates. First, a three‐dimensional (3D) thermal analysis model was established. Then, a modified eletrothemal expression was proposed to predict thermal effects including scalability. For validation, the proposed model was implemented into quasi‐physics zone division (QPZD) large‐signal model. Results show that the proposed model accurately predicts theI–Vcurves of devices with different gate widths, gate fingers, and ambient temperatures. Moreover, the results of the model are consistent with on‐wafer measurements of 2 × 125, 4 × 125, and 10 × 50 μm of GaN‐on‐diamond HEMTs, indicating that the proposed model accurately predicts the DC–IVcurves, scattering parameters, and large‐signal performance. The findings of this study can be useful for designing microwave diamond–GaN HEMT circuits.