Effects of silicon doping and threading dislocation density on stress evolution in AlGaN films

Joan Marie Redwing, Ian C. Manning, Xiaojun Weng, Sarah M. Eichfeld, Jeremy D. Acord, Mark Andrew Fanton, David W. Snyder

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In-situ wafer curvature measurements were used to study the effect of Si doping on intrinsic growth stress during the metalorganic chemical vapor deposition (MOCVD) growth of Al xGa 1-xN (X=0-0.62) layers on SiC substrates. Post-growth transmission electron microscopy (TEM) characterization was used to correlate measured changes in stress with changes in film microstructure. Si doping was found to result in the inclination of edge-type threading dislocations (TDs) in Al xGa 1-xN which resulted in a relaxation of compressive stress and generation of tensile stress. The experimentally measured stress gradient was similar to that predicted by an effective climb model. Dislocation inclination resulted in a reduction in the TD density for Si-doped layers compared to undoped Al xGa 1-xN likely due to increased opportunities for dislocation interaction and annihilation. The TD density, which increased with increasing Al-fraction, was found to significantly alter the stress gradients in the films. Film stress was also observed to play a role in TD inclination. In undoped Al xGa 1-xN, TD inclination was observed only when the film grew under a compressive stress while in Si-doped Al xGa 1-xN, TD inclination was observed independent of the sign or magnitude of the film stress. Si dopants are believed to alter the concentration of surface vacancies which gives rise to dislocation jog via a surface-mediated climb mechanism.

Original languageEnglish (US)
Title of host publicationCompound Semiconductors for Generating, Emitting and Manipulating Energy
Pages183-191
Number of pages9
DOIs
StatePublished - Aug 20 2012
Event2011 MRS Fall Meeting - Boston, MA, United States
Duration: Nov 28 2011Dec 2 2011

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1396
ISSN (Print)0272-9172

Other

Other2011 MRS Fall Meeting
CountryUnited States
CityBoston, MA
Period11/28/1112/2/11

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Redwing, J. M., Manning, I. C., Weng, X., Eichfeld, S. M., Acord, J. D., Fanton, M. A., & Snyder, D. W. (2012). Effects of silicon doping and threading dislocation density on stress evolution in AlGaN films. In Compound Semiconductors for Generating, Emitting and Manipulating Energy (pp. 183-191). (Materials Research Society Symposium Proceedings; Vol. 1396). https://doi.org/10.1557/opl.2012.215