New nanometer T-gate fabricated by thermally reflowed resist technique

Abstract

Novel nanometer T-gate process has been developed utilizing electron beam (EB) lithography and thermally reflowed resist technique. Through well-controlled EB exposure dosage, heating time and reflow temperature; the resist structures can be efficiently reflowed to form the desired T-gate configuration with dimension ranging from 150 nm to 30 nm. After Ti/Pt/Au metal deposition by electron gun evaporation and lift-off process, the nanometer T-gates with thickness of about 500 nm were formed. With the optimized conditions, ultra-short 30 nm T-shaped gate was clearly demonstrated on the GaAs substrate. This is the smallest T-gate reported with the thermally reflowed technique in the literature so far and can practically be used in the GaAs monolithic microwave integrated circuit (MMIC) fabrications.