Fabrication of submicron T-gate GaAs FET and preamplifier

Abstract

Submicron T-Gate GaAs FET is fabricated. It uses 1㎛ FET photolithography process. So, its process has high productivity and low cost. Fabricated FET has $L_g$ of 0.4㎛, $g_m$ of 173 mS/mm, $f_T$ of 32 GHz and $f_T$ of 64 GHz. Using T-Gate FET, preamplifier for optical communication is designed and fabricated. Fabricated amplifier has bandwidth of 1.7 GHz, transimpedance of 66.5 dBΩ, and $S_22$ under -15 dB. The laser lithography system for mask fabrication is developed. The minimum line width for fine pattern is 2.5 ㎛.