Fabrication of 0.15-$\mu\hbox{m}$ $\Gamma$-Shaped Gate $\hbox{In}_{0.52}\hbox{Al}_{0.48}\hbox{As}/\hbox{In}_{0.6}\hbox{Ga}_{0.4}\hbox{As}$ Metamorphic HEMTs Using DUV Lithography and Tilt Dry-Etching Technique

An In
_0.52
Al
_0.48
As/In
_0.6
Ga
_0.4
As metamorphic high-electron mobility transistor (MHEMT) with 0.15-mum Gamma-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-mum In
_0.52
Al
_0.48
As/In
_0.6
Ga
_0.4
As 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
_max
of 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