E-beam process control for the fabrication of T-shaped gates for GaAs MESFETs with dimensions down to 80 nm

Novel electron beam lithography technique for submicron T-gate fabrication

“…4,5 T-shaped gate fabrication using the multilayer resist process has been reported by many authors. [6][7][8] In this technique polymethylmethacrylate ͑PMMA͒ and its methacrylic acid copolymer ͑PMMA-MAA͒ are used as a low ͑LO͒ and high ͑HI͒ sensitive resists, respectively. Two or three coating of these resists as HI/LO or LO/HI/LO, and use of tailored energy deposition provide a T-gate profile.…”