Damage-free top-down processes for fabricating two-dimensional arrays of 7 nm GaAs nanodiscs using bio-templates and neutral beam etching

Abstract

The first damage-free top-down fabrication processes for a two-dimensional array of 7 nm GaAs nanodiscs was developed by using ferritin (a protein which includes a 7 nm diameter iron core) bio-templates and neutral beam etching. The photoluminescence of GaAs etched with a neutral beam clearly revealed that the processes could accomplish defect-free etching for GaAs. In the bio-template process, to remove the ferritin protein shell without thermal damage to the GaAs, we firstly developed an oxygen-radical treatment method with a low temperature of 280 °C. Then, the neutral beam etched the defect-free nanodisc structure of the GaAs using the iron core as an etching mask. As a result, a two-dimensional array of GaAs quantum dots with a diameter of ∼ 7 nm, a height of ∼ 10 nm, a high taper angle of 88° and a quantum dot density of more than 7 × 10(11) cm(-2) was successfully fabricated without causing any damage to the GaAs.

Electron g-factor and spin decoherence in GaAs quantum nanodisks fabricated by fully top-down lithography

“…Quantum nanodisks (NDs) of GaAs with desirable optical qualities have recently been grown from quantum wells (QWs) by fully top-down lithography, using damage-free neutral-beam etching aided by bioengineering [1][2][3][4]. This fabrication method allows us to flexibly design the structural parameters of the NDs.…”

Photoluminescence of InGaAs/GaAs Quantum Nanodisk in Pillar Fabricated by Biotemplate, Dry Etching, and MOVPE Regrowth

“…At the GaAs interface, plasma damage has been reported up to a depth of several tens of nanometers from the etching interface . To overcome this issue, minimally damaging etching systems have been developed for GaAs systems. − …”

High Density and High Aspect Ratio GaAs/AlGaAs Nanopillar array Fabricated by Fusion of Bio-Template and Neutral Beam Etching

“…This process uses 7-nm-diameter metal oxide cores inserted in a cage-like protein (ferritin) as the etching masks. NBE is used to etch GaAs wafers without defects in the nanostructures [5][6][7].…”