Scalable digital atomic precision lithography

Abstract

Current lithographic techniques are limited to a resolution of a few nm with poor relative precision. Scanning Tunneling Microscope (STM) based lithography[1], removes H from H-passivated Si 2x1 (100) by a mode distinct from usual imaging. This technique is generally called Hydrogen Depassivation Lithography (HDL) and since it scans a beam of electrons around on a surface exposing a resist, it is a form of E-beam Lithography. The HDL approach is not effective with standard resists and, at present, has only a limited number of pattern transfer methods. The two primary ones are patterning 2D delta doped Si devices for solid state quantum devices and selective Atomic Layer Deposition metal oxides that can be used as hard etch masks. However, electron stimulated desorption of atoms and molecules is a fairly generic process and its use can be anticipated on a wide variety of substrates. Sub-nm resolution (0.768 nm) has been demonstrated and used for numerous research purposes, such as dopant positioning for quantum devices[2]. While sub-nm resolution is easily obtainable with standard Ultra-High Vacuum (UHV) STMs, the repeatability and accuracy of the patterning has limited its applications. In this paper we report on progress to dramatically scale HDL’s throughput while maintaining sub-nm resolution.