Lithography-independent and large scale fabrication of a metal electrode nanogap

Abstract

A lithography-independent and wafer scale method to fabricate a metal nanogap structure is demonstrated. Polysilicon was first dry etched using photoresist (PR) as the etch mask patterned by photolithography. Then, by depositing conformal SiO2 on the polysilicon pattern, etching back SiO2 anisotropically in the perpendicular direction and removing the polysilicon with KOH, a sacrificial SiO2 spacer was obtained. Finally, after metal evaporation and lifting-off of the SiO2 spacer, an 82 nm metal-gap structure was achieved. The size of the nanogap is not determined by the photolithography, but by the thickness of the SiO2. The method reported in this paper is compatible with modern semiconductor technology and can be used in mass production.

Process development of 40 nm silicon nanogap for sensor application

“…Each method described its own advantages and characteristics with successfully achieved a gap as small as 10 nm. Several methods has been integrated and adopted into the development process to obtain a good size of gap for improving molecules detection function in nanogap based sensor [4][5][6][7][8].…”