S-Graded Buffet Layers for Lattice-Mismatched Heteroepitaxial Devices

We have conducted a theoretical study of the equilibrium strain and misfit dislocation density profiles for "S-graded" buffer layers of In sub(x)Ga sub(1-x) As on GaAs (001) substrates in which the compositional profile follows a normal cumulative distribution function. On the basis of thi...

Full description

Saved in:
Bibliographic Details
Published in:Journal of electronic materials 2011-12, Vol.40 (12), p.2348-2354
Main Authors: Xhurxhi, S, Obst, F, Sidoti, D, Bertoli, B, Kujofsa, T
Format: Article
Language:English
Subjects:
Buffer layers
Density
Devices
Dislocation density
Gallium arsenide
Optimization
Surface chemistry
Threading dislocations
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We have conducted a theoretical study of the equilibrium strain and misfit dislocation density profiles for "S-graded" buffer layers of In sub(x)Ga sub(1-x) As on GaAs (001) substrates in which the compositional profile follows a normal cumulative distribution function. On the basis of this modeling work we show that the S-graded layer exhibits misfit dislocation-free regions near the substrate interface and the free surface (or device interface). The equilibrium peak misfit dislocation density as well as the thicknesses of the dislocation-free regions may be tailored by design of the compositional profile; this in turn should enable minimization of the density of electronically active threading dislocations at the top surface. S-graded buffer layers may therefore facilitate the achievement of metamorphic device structures with improved performance compared with similar structures having uniform or linearly graded buffers.
ISSN:0361-5235