Fabrication of 0.15-μ Γ-shaped Gate In_0.52 Al_0.48As/In_0.6Ga_0.4 metamorphic HEMTs using DUV lithography and tilt dry-etching technique

An In_0.52Al_0.48As/In_0.6Ga_0.4 As metamorphic high-electron mobility transistor (MHEMT) with 0.15-μΓ-shaped gate using deep ultraviolet lithography and tilt dry-etching technique is demonstrated. The developed submicrometer gate technology is simple and of low cost as compared to the conventional E-beam lithography or other hybrid techniques. The gate length is controllable by adjusting the tilt angle during the dry-etching process. The fabricated 0.15-μ In_0.52Al_0.48 As/In_0.6Ga_0.4 MHEMT using this novel technique shows a saturated drain-source current of 680 mA/mm and a transconductance of 728 mS/mm. The f_T and f_maxof the MHEMT are 130 and 180 GHz, respectively. The developed technique is a promising low-cost alternative to the conventional submicrometer E-beam gate technology used for the fabrication for GaAs MHEMTs and monolithic microwave integrated circuits.