Analysis of Trapping Mechanisms and Capacitance Dispersion in Double-π Gate AlGaN/GaN HEMTs Under High-Temperature Conditions

High-temperature dc and ac capacitance dispersion analysis of the double- $\pi $ gate AlGaN/GaN high electron mobility transistor (HEMT) is simulated to analyze the trapping effects. Self-heating phenomena in electronic devices degrade both performance and lifetime. Self-heating effects (SHE) lead to a rise in channel temperature, which directly impacts the bandgap (EG), mobility of the electrons ( $\mu _{e}$ ), electron saturation velocity (Vsat), threshold voltage (VTH), breakdown voltage (VBD), transconductance (gm), drain saturation current (IDS), output power (Pout) as well as memory effects and noise performance. To mitigate self-heating effects, a new double- $\pi $ gate HEMT is designed with the gate stem divided into three pillars. This structure redistributes the electric field and reduces phonon scattering. Notably, the device current collapse (CC) percentage drastically decreased when operated at high temperature. Capacitance dispersion is simulated using 2-D TCAD across ambient temperatures ranging from 253°K to 1098°K. Simulation results showed minimal hot electron generation and trapping effects at extreme temperatures. A slight kink effect is observed at temperatures above 773°K for gate stem distances greater than 150 nm.