Estimation of Zero-Field Activation Energy for Traps in Fe-and C-Doped GaN-Based HEMTs

Carrier emission rate accelerates from a trap with the increase in drain voltage due to the self-heating (SH) and Poole-Frenkel (PF) emission effects; thus, the conventional Arrhenius analysis underestimates the trap activation energy. For this purpose, this work estimates the zero-field (actual) activation energy of a trap in InAlN/GaN and AlN/GaN high-electron mobility transistors (HEMTs) by including SH and PF effects in the emission rate equation. The HEMT thermal resistance (R-TH) is computed from the technology computer aided design (TCAD) simulation results. Subsequently, the SH-induced increase in the channel temperature (?T) is incorporated in the Arrhenius plot, constructed from drain current transient (DCT) and output-admittance (Y-22) parameters. The apparent trap activation energy (E-ap) is calculated from the measured DCT and Y-22 at different drain voltages, and the respective electric field (F) at each bias condition is extracted from the simulation. Finally, zero-field activation energy (E-0) is estimated from the E(ap )versus (F )(0.5 )plot intercept. E-0 for the well-known Fe-related buffer trap is identified at EC-0.7 eV in the InAlN/GaN HEMT. Similarly, E-0 at E-C - 0.51 eV is found for the trap in the C-doped AlN/GaN HEMT.

Automated summary

This work estimates the zero-field activation energy of traps in InAlN/GaN and AlN/GaN HEMTs by incorporating self-heating and Poole-Frenkel effects in the emission rate equation. The HEMT thermal resistance is computed from TCAD simulation results and the channel temperature increase caused by self-heating is included in the Arrhenius plot. The apparent trap activation energy is calculated from measured parameters at different drain voltages and the electric field at each bias condition is extracted from simulation.