Effect of gate length on DC performance of AlGaN/GaN HEMTs grown by MBE

The DC performance of AlGaN/GaN high electron mobility transistors grown by plasma-assisted molecular beam epitaxy was investigated for gate lengths in the range 0.1–1.2 μm. On 0.25 μm gate length devices we obtained 40 VDS operation with >50 mA peak ID. The peak drain current density was 0.44 A/mm for 100 μm gate width devices with 1.2 μm gate lengths. The extrinsic transconductance (gm) decreased with both gate length and gate width and was ⩾75 mS/mm for all gate widths for 0.25 μm devices. E-beam written gates typically produced a slightly lower Schottky barrier height than optically patterned gates.