Fabrication of 30nm T-gate high electron mobility transistors using a bi-Layer of PMMA and UVIII

This work reports on the development and fabrication of High Electron Mobility Transistors with a gate length of less than 30nm. The T-shaped gates were realized using a two-stage "bi-lithography" process that creates a T-shaped image in a bilayer of PMMA and UVIII. This is then transferred into SiO<sub>2</sub> gate support layer by a low damage dry-etch process. This method enables the fabrication of mechanically robust, ultra short T-gates to be realised