title: Highly selective dry etching of germanium over germanium-tin (Ge(1-x)Sn(x)): a novel route for Ge(1-x)Sn(x) nanostructure fabrication.
abstract: We present a new etch chemistry that enables highly selective dry etching of germanium over its alloy with tin (Ge(1-x)Sn(x)). We address the challenges in synthesis of high-quality, defect-free Ge(1-x)Sn(x) thin films by using Ge virtual substrates as a template for Ge(1-x)Sn(x) epitaxy. The etch process is applied to selectively remove the stress-inducing Ge virtual substrate and achieve strain-free, direct band gap Ge0.92Sn0.08. The semiconductor processing technology presented in this work provides a robust method for fabrication of innovative Ge(1-x)Sn(x) nanostructures whose realization can prove to be challenging, if not impossible, otherwise.
authors.affiliation: Department of Electrical Engineering, Stanford University, Stanford, California 94305, United States. suyog@stanford.edu
authors.forename: Suyog
authors.initials: S
authors.lastname: Gupta
authors.forename: Robert
authors.initials: R
authors.lastname: Chen
authors.forename: Yi-Chiau
authors.initials: YC
authors.lastname: Huang
authors.forename: Yihwan
authors.initials: Y
authors.lastname: Kim
authors.forename: Errol
authors.initials: E
authors.lastname: Sanchez
authors.forename: James S
authors.initials: JS
authors.lastname: Harris
authors.forename: Krishna C
authors.initials: KC
authors.lastname: Saraswat