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Title: Etching of germanium-tin using ammonia peroxide mixture

The wet etching of germanium-tin (Ge{sub 1-x}Sn{sub x}) alloys (4.2% < x < 16.0%) in ammonia peroxide mixture (APM) is investigated. Empirical fitting of the data points indicates that the etch depth of Ge{sub 1-x}Sn{sub x} is proportional to the square root of the etch time t and decreases exponentially with increasing x for a given t. In addition, X-ray photoelectron spectroscopy results show that increasing t increases the intensity of the Sn oxide peak, whereas no obvious change is observed for the Ge oxide peak. This indicates that an accumulation of Sn oxide on the Ge{sub 1-x}Sn{sub x} surface decreases the amount of Ge atoms exposed to the etchant, which accounts for the decrease in etch rate with increasing etch time. Atomic force microscopy was used to examine the surface morphologies of the Ge{sub 0.918}Sn{sub 0.082} samples. Both root-mean-square roughness and undulation periods of the Ge{sub 1-x}Sn{sub x} surface were observed to increase with increasing t. This work provides further understanding of the wet etching of Ge{sub 1-x}Sn{sub x} using APM and may be used for the fabrication of Ge{sub 1-x}Sn{sub x}-based electronic and photonic devices.
Authors:
; ; ; ; ;  [1] ; ;  [2] ;  [3]
  1. Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore)
  2. Institute of Material Research and Engineering, A*STAR (Agency for Science, Technology and Research), 2 Fusionopolis Way, #08-03, Innovis, Singapore 138634 (Singapore)
  3. Department of Physics, National University of Singapore, Singapore 117551 (Singapore)
Publication Date:
OSTI Identifier:
22493105
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 118; Journal Issue: 24; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AMMONIA; ATOMIC FORCE MICROSCOPY; ETCHING; GERMANIUM ALLOYS; GERMANIUM OXIDES; MORPHOLOGY; PEROXIDES; ROUGHNESS; SURFACES; TIN ALLOYS; TIN OXIDES; X-RAY PHOTOELECTRON SPECTROSCOPY