Materials properties and dislocation dynamics in InAsP compositionally graded buffers on InP substrates
Author(s)Jandl, Adam Christopher; Bulsara, Mayank; Fitzgerald, Eugene A.
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The properties of InAs [subscript x]P1[subscript −x] compositionally graded buffers grown by metal organic chemical vapor deposition are investigated. We report the effects of strain gradient (ε/thickness), growth temperature, and strain initiation sequence (gradual or abrupt strain introduction) on threading dislocation density, surface roughness, epi-layer relaxation, and tilt. We find that gradual introduction of strain causes increased dislocation densities (>10[superscript 6]/cm[superscript 2]) and tilt of the epi-layer (>0.1°). A method of abrupt strain initiation is proposed which can result in dislocation densities as low as 1.01 × 10[superscript 5] cm[superscript −2] for films graded from the InP lattice constant to InAs [subscript 0.15]P[subscript 0.85]. A model for a two-energy level dislocation nucleation system is proposed based on our results.
DepartmentMassachusetts Institute of Technology. Department of Materials Science and Engineering
Journal of Applied Physics
American Institute of Physics
Jandl, Adam, Mayank T. Bulsara, and Eugene A. Fitzgerald. “Materials Properties and Dislocation Dynamics in InAsP Compositionally Graded Buffers on InP Substrates.” Journal of Applied Physics 115, no. 15 (April 21, 2014): 153503. © 2014 AIP Publishing LLC.
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