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 language | English (US) |
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Pages (from-to) | 916-925 |
Number of pages | 10 |
Journal | IEEE Journal on Selected Topics in Quantum Electronics |
Volume | 3 |
Issue number | 3 |
DOIs | |
State | Published - Jun 1997 |
Externally published | Yes |
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