Strain relaxation due to V-pit formation in In[sub x]Ga[sub 1−x]N∕GaN epilayers grown on sapphire

Citation

Song, T. L. (2005) Strain relaxation due to V-pit formation in In[sub x]Ga[sub 1−x]N∕GaN epilayers grown on sapphire. Journal of Applied Physics, 98 (8). 084906. ISSN 00218979

Full text not available from this repository.

Abstract

Strain relaxation in semiconductor heterostructures generally occurs through the motion of dislocations that generates misfit dislocations above a critical thickness. However, majority of the threading dislocations in GaN-related materials have no driving force to glide, and those with a driving force are kinetically impeded even at a temperature of 1000 degrees C. In spite of this, the strain in InxGa1-xN/GaN epilayers grown on c-plane sapphire substrates was observed to decrease as the InxGa1-xN layer becomes thicker. We have explored the possibility of V-pit formation at terminated dislocations as the predominant relaxation mechanism in highly mismatched systems such as InxGa1-xN/GaN. We demonstrate that a driving force exists to nucleate V pits for strain relief. The formation of V pits was modeled through the energy balance between the strain energy in the InxGa1-xN epilayer, the destruction of dislocation energy to form V pits and the strain that is relieved due to the formation of edges during the process of nucleating V pits in thermal equilibrium. V-pit formation and growth lead to strain relief as the film becomes thicker. The model illustrates many features that correlate reasonably well with experimental observations; the most significant trends are a rise in V-pit density and a decrease in strain with increasing layer thickness. (c) 2005 American Institute of Physics.

Item Type: Article
Subjects: Q Science > QC Physics
Divisions: Faculty of Engineering (FOE)
Depositing User: Ms Rosnani Abd Wahab
Date Deposited: 12 Sep 2011 06:24
Last Modified: 12 Sep 2011 06:24
URII: http://shdl.mmu.edu.my/id/eprint/2177

Downloads

Downloads per month over past year

View ItemEdit (login required)