Advances in selective wet oxidation of AlGaAs alloys

Kent D. Choquette, Kent M. Geib, Carol I.H. Ashby, Ray D. Twesten, Olga Blum, Hong Q. Hou, David M. Follstaedt, B. Eugene Hammons, Dave Mathes, Robert Hull

Research output: Contribution to journalArticlepeer-review

Abstract

We review the chemistry, microstructure, and processing of buried oxides converted from AlGaAs layers using wet oxidation. Hydrogen is shown to have a central role in the oxidation reaction as the oxidizing agent and to reduce the intermediate product As 2O 1 to As. The stable oxide is amorphous (Al xGa 1 - x) 2O 3 which has no defects along the oxide/semiconductor interfaces but can exhibit strain at the oxide terminus due to volume shrinkage. The influence of gas flow, gas composition, temperature, Al-content, and layer thickness on the oxidation rate are characterized to establish a reproducible process. Linear oxidation rates with Arrhenius activation energies which strongly depend upon AlAs mole fraction are found. The latter produces strong oxidation selectivity between AlGaAs layers with slightly differing Al-content. Oxidation selectivity to thickness is also shown for layer thickness <60 nm. Differences between the properties of buried oxides converted from AlGaAs and AlAs layers and the impact on selectively oxidized vertical cavity laser lifetime are reported.

Original languageEnglish (US)
Pages (from-to)916-925
Number of pages10
JournalIEEE Journal on Selected Topics in Quantum Electronics
Volume3
Issue number3
DOIs
StatePublished - Jun 1997
Externally publishedYes

Keywords

  • Materials processing
  • Materials science and technology
  • Optoelectronic device
  • Semiconductor device fabrication
  • Semiconductor lasers

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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