Positive electron beam resists for lithography below 5 nm

We compare two promising new positive self-developing electron beam resists that enable the direct patterning of nanostructures at the 1–5 nm scale. Myo-inositol is a positive organic resist that can be exposed to provide line and dot gratings with 8 nm pitch at a dose of 6 nC/cm. YbF2 provides better resolution in thick films as it is mechanically stronger, and we show line and dot gratings with 5 nm pitch at a dose of 80 nC/cm. Both of these resists were deposited by vapor deposition, and their exposure conditions were compared by exposing and imaging resist patterns in a scanning transmission electron microscope with a 0.2 nm spot size at 40–160 kV. 5 nm feature sizes were demonstrated in 90–100 nm thick layers of both materials.