On the spatial resolution limit of direct-write electron beam lithography

Abstract

The mechanism for direct-write electron-beam lithography in insulating resists is introduced in this letter, and it is based on damage by the induced electric field in transmission electron microscope. Under this mechanism, the direct-write EBL is electron dose-rate dependent, and there is a dose-rate threshold, below which the lithographic process does not operate, regardless of the total electron dose. The spatial resolution is determined by the strength of the induced electric field. In theory, the highest spatial resolution should be set by the dimension of the electron beam, and thus the EBL should be able to create nanostructures at the atomic scale. So far, the best resolution obtained was in the direct write of conductive nanochannels in Li4Ti5O12, in which 1.5nm isolated features and a 1.0–1.5nm half-pitch array of nanochannels were achieved.