Toward sub-20 nm hybrid nanofabrication by combining the molecular ruler method and electron beam lithography

It is of great interest and importance to develop new nanofabrication processes to fabricate sub-20 nm structures with sub-2 nm resolution for next-generation nanoelectronic devices. A combination of electron beam lithography (EBL) and a molecular ruler is one of the promising methods to make these fine structures. Here we successfully develop a hybrid method to fabricate sub-20 nm nanogap devices at the desired positions with a complex structure by developing a post-EBL process, which enabled us to avoid damaging the molecular ruler with the high-energy electron beam, and to fully utilize the EBL resolution. It was found that slight etching of the Ti adhesion layer of the parent metal (Pt) by ACT935J solution assisted the removal of molecular rulers, resulting in improved enhancement in the product yield (over 70%) of nanogap devices.