- Losurdo, M. and Capezzuto, P. and Bruno, G. and Namkoong, G. and Doolittle, W.A. and Brown, A.S., The chemistry of sapphire nitridation in relation to the GaN structural quality: Why low temperature 200°C nitridation?,
Phys. Status Solidi A (Germany), vol. 188 no. 2
pp. 561 - 5 [1521-396X(200112)188:2<561::AID-PSSA561>3.0.CO;2-J] .
(last updated on 2007/04/14)
The effect of c-plane sapphire nitridation upon exposure to an rf N2 plasma at temperatures in the range 100-700°C on the quality of GaN epilayers grown by MBE is investigated. A homogeneous AlN layer is formed at 200°C. Nitridation at higher temperatures creates a rough and non-homogeneous nitridated layer including both AlN and NO. Lowering the nitridation temperature to 200°C results in the improvement of the GaN structural and photoluminescence properties. The results are interpreted in the framework of a chemical model based on the competition between formation of AlN and NO whose adsorption/desorption equilibrium on the sapphire surface strongly depends on temperature
annealing;chemisorption;gallium compounds;III-V semiconductors;nitridation;photoluminescence;sapphire;semiconductor epitaxial layers;semiconductor growth;substrates;thermally stimulated desorption;wide band gap semiconductors;