0.15-mu m T-shaped gate MODFETs using BCB as low-k spacer

We report 0.15-mum T-shaped gate MODFETs using BCB (Benzocyclobutene) as lo w-k spacer dielectric material. The RF performance of pseudomorphic MODFET was improved by reducing the gate fringing capacitance using low-k material . The BCB film was deposited by plasma CVD technique at 100 degreesC and wa s patterned by lift-off technique. The dielectric constant of BCB film depo sited by plasma CVD was confirmed 2.7, which is equal to that of spin-coate d BCB, and is 35% lower than that of conventional SiO2. The leakage current was 4.7 x 10(-5) A/cm(2) at 3.6 MV/cm and was low enough for spacer materi al. 0.15-mum T-shaped gate MODFETs were fabricated by using BCB spacer and phase-shift lithography technique. More than 20 GHz increase of f(max) was obtained in comparison with conventional SiO2 spacer by reducing the gate f ringing capacitance.