T-gate fabrication using a ZEP520A/UVIII bilayer

This paper reports a new electron beam lithography (EBL) technique for T-gates fabrication using a ZEP520A/UVIII resist stack. The process enables T-gates with sub-100 nm footwidths to be fabricated routinely. Contrast curve methods were used to optimise processing parameters for the ZEP520A foot layer and the UVIII head layer. Both resists demonstrate a high sensitivity towards electron beam exposure with a large sensitivity ratio between the head and foot layers. The resist stack is thus well suited to patterning T-shaped profiles and the total writing time for T-gate patterns is less than for PMMA/UVIII bilayers. (C) 2001 Elsevier Science B.V. All rights reserved.