Unique resist profiles with Be and Si focused ion beam lithography

Abstract

The delineation of resist patterns has been investigated for two kinds of ions, Be and Si. Patterns consisting of 0.2 μm lines and spaces were fabricated in 0.7 μm thick resist with good repeatability and accuracy. This shows that the influence of proximity effects can be disregarded. The broadening of patterns was observed for Si exposure because of the more significant influence of recoil atoms. As a special application of focused ion beam lithography, a new process for fabricating a mushroom gate electrode for a GaAs microwave field-effect transistor (FET) was demonstrated utilizing the particular exposure characteristics of the different ion species.