Fabrication of Germanium Tin Microstructures Through Inductively Coupled Plasma Dry Etching
Date
2021-09-30
Journal Title
Journal ISSN
Volume Title
Publisher
IEEE Transactions on Nanotechnology
Abstract
Germanium tin (GeSn) with a Sn content of >12% has a great potential for optoelectronic devices due to its direct bandgap property. In this work, the anisotropic etching of GeSn with Sn content of 12.5% and selective etching of Ge over GeSn were explored by inductively couple plasma (ICP) dry etching to obtain various microstructures. Through adding oxygen into chlorine and argon and adjusting the process pressure, the anisotropic etching of GeSn was optimized with an ideal sidewall angle of 89 o . The optimized process is compatible with both positive and negative resists. By altering the ICP power, Ge etching recipes with low and high etching rates were developed, which are favorable for fabricating GeSn nano- and micro-structures, respectively. An etching selectivity of >126 for Ge over GeSn with Sn content of >10% can be achieved. With the optimized dry etching recipes, suspended GeSn microribbons and microdisks were realized. Ultimately, the suspended GeSn microstructures were transferred onto 40-nm-thick ZrO 2 on p + -Si to form a GeSn-on-insulator (GeSnOI) substrate. For a fabricated 45-nm-thick Ge 0.875 Sn 0.125 OI back-gated transistor, the subthreshold swing (SS) of 240 mV/dec is reasonably low for a non-optimized device, suggesting that the explored dry etching methods are promising for device processing.
Description
Copyright 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. This article was originally published in IEEE Transactions on Nanotechnology. The version of record is available at: https://doi.org/10.1109/TNANO.2021.3115509
Keywords
Germanium tin, inductively coupled plasma, anisotropic etching, selective etching, germanium tin on insulator
Citation
G. Lin et al., "Fabrication of Germanium Tin Microstructures Through Inductively Coupled Plasma Dry Etching," in IEEE Transactions on Nanotechnology, vol. 20, pp. 846-851, 2021, doi: 10.1109/TNANO.2021.3115509.