A 149W recessed-gate AlGaN/GaN FP-FET

A recessed-gate AlGaN/GaN field-modulating plate (FP) FET was successfully fabricated on a SiC substrate. By employing recessed-gate structure for an FP-FET, the transconductance (gm) was increased from 130 mS/mm to 220 mS/mm, leading to an improvement in gain characteristics. The gate breakdown voltage (BV_gd) was improved from 160V for the planar FP-FET to 200V for the recessed FP-FET, resulting from one-order reduction in gm and BV_gd, current collapse was suppressed by introducing the recessed-gate structure. At 2GHz, a 32mm-wide recessed FP-FET exhibited an output power of 149 W (4.7W/mm) with 64% power-added efficiency and 8.7 dB linear gain with a drain bias of 47 V.