Source‐Connected Field‐Plate Effects on Static Current, Trap Signature, and Thermal Resistance of AlGaN/GaN High Electron Mobility Transistor

The source‐connected field‐plate (SC‐FP) effects on the electrical, trapping, and thermal characteristics of 150 nm AlGaN/GaN high electron mobility transistors (HEMTs) are investigated, relative to the unterminated HEMT. Static electrical characterization reveals that the SC‐FP structure reduces drain current ( I DS ) and subthreshold leakage current compared to the FP‐free devices, due to the decrease in peak electric field. Alongside, gate leakage current ( I GS ) is considerably mitigated, with the improvement in subthreshold slope. The drain current transient (DCT) and output‐admittance ( Y 22 ) measurements indicate that the emission time constant of the buffer trap prolongs in the SC‐FP HEMT, because of moderated Poole‐Frenkel emission. This results in a marginally higher activation energy for the buffer trap. At the same time, the SC‐FP structure mitigates the electron trapping in the HEMT, as identified from the DCT and Y 22 signal amplitude. A methodology is established to estimate the thermal resistance ( R TH ) directly from the DCT experiments, conducted at different dissipated powers and temperatures. Using this DCT method, the effective R TH of the HEMT with and without SC‐FP is reported. The experimental observations are also substantiated with technology computer‐aided design (TCAD) simulation findings, enabling a comprehensive understanding of the underlying physical mechanisms governing the macroscopic transistor characteristics.