Accession Number:

ADA591473

Title:

Structural and Optical Studies of Thick Freestanding GaN Films Deposited by Hydride Vapor Phase Epitaxy

Descriptive Note:

Journal article

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC

Report Date:

2012-01-01

Pagination or Media Count:

7.0

Abstract:

Thick freestanding films or bulk GaN substrates with very low background impurity levels 1 x10expn 15cmexpn 3 and high crystalline quality are required for a number of electronic device applications. Low pressure chemical vapor and molecular beam epitaxy techniques can systematically deposit films with low residual impurity concentrations. However, their typical slow growth rate prevents their utilization for substrate growth. The hydride vapor phase epitaxy deposition technique can achieve hundreds of microns per hour growth rate, but these films have typically high free carrier concentration 3 x 10expn 17cmexpn 3. It is crucial to verify if this method can reproducibly deliver thick freestanding GaN films of high crystalline quality with exceptionally low free carrier concentration. Low temperature photoluminescence and room temperature Raman scattering experiments carried out on a number of samples indicate that they have high crystalline quality and uncommonly low donor background levels. Reduced concentration of uncompensated shallow donors verified by low temperature electron paramagnetic resonance was confirmed by detailed high sensitive SIMS analyses. In addition, it was verified by X-ray diffraction analysis that relatively low dislocation densities can be achieved.

Subject Categories:

  • Chemistry
  • Physical Chemistry
  • Crystallography
  • Optics
  • Solid State Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE