Impact of lateral scaling on the electrical characteristics of AlGaN/GaN HEMTs

This study systematically analyzes the effects of lateral scaling on the direct current (DC) and radio frequency (RF) characteristics of AlGaN/GaN high‐electron‐mobility transistors (HEMTs) by varying the geometric parameters gate length ( L G ), gate width ( W G ), number of fingers ( N F ), source‐to‐gate distance ( L SG ), and source‐to‐drain distance ( L SD ). L G scaling enhances transconductance ( g m ) and cut‐off frequency ( f T ) but strengthens short‐channel effects and reduces breakdown voltage ( V BR ). Drain current ( I D ) remains largely constant across varying W G and N F , but changes in these parameters significantly affect RF characteristics because of increased parasitic capacitance and gate resistance ( R G ). A reduced L SG enhances DC performance by increasing I D and g m but minimally impacts RF characteristics thanks to increased gate‐to‐source parasitic capacitance ( C gs ). Decreasing L SD significantly boosts f T and maximum oscillation frequency ( f max ) by reducing carrier transit time, but severely reduces V BR by enhancing electric field concentration. These findings provide a detailed understanding of the geometric dependencies and offer design guidelines for optimizing DC and RF performance.