Defect investigation of GaN thin films etched by photo-electrochemical and hot wet etching by atomic force and transmission electron microscopy

P. Visconti, K. M. Jones, M. A. Reshchikov, R. Cingolani, H. Morkoç, R. J. Molnar, David Smith

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

1 Scopus citations

Abstract

The availability of reliable and quick methods to investigate defects in GaN films is of great interest. Photo-electrochemical (PEC), and hot wet etching using both H3PO4 acid and molten KOH have been used to study structural defects in GaN layers grown by hydride vapor phase epitaxy and molecular beam epitaxy. The purpose of this work is to determine whether, and under what conditions, these different methods of investigation are consistent and to get to a more accurate estimation of the defect density. As-grown and etched surfaces were investigated by atomic force microscopy (AFM), and plan-view and cross-sectional transmission electron microscopy (TEM). Free-standing whisker-like features and hexagonal etch pits were formed on the etched sample surfaces by PEC and wet etching, respectively. Using plan-view AFM, we found the density of whiskers (8×108-1 × 10 9 cm-2) to be similar to the etch pit densities when etched in both H3PO4 and molten KOH under precise etching conditions. During the wet etching process, a careful balance must be struck to ensure that every defect is delineated, but not overetched to cause merging which would lead to an underestimation of the defect density. Additionally, TEM observations confirmed the dislocation densities obtained by etching, which increased our confidence in the consistency of the methods used.

Original languageEnglish (US)
Title of host publicationWide-Bandgap Electronics
PublisherMaterials Research Society
Pages162-167
Number of pages6
ISBN (Print)1558996168, 9781558996168
DOIs
StatePublished - 2001
Event2001 MRS Spring Meeting - San Francisco, CA, United States
Duration: Apr 16 2001Apr 20 2001

Publication series

NameMaterials Research Society Symposium Proceedings
Volume680
ISSN (Print)0272-9172

Other

Other2001 MRS Spring Meeting
CountryUnited States
CitySan Francisco, CA
Period4/16/014/20/01

ASJC Scopus subject areas

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

Fingerprint Dive into the research topics of 'Defect investigation of GaN thin films etched by photo-electrochemical and hot wet etching by atomic force and transmission electron microscopy'. Together they form a unique fingerprint.

  • Cite this

    Visconti, P., Jones, K. M., Reshchikov, M. A., Cingolani, R., Morkoç, H., Molnar, R. J., & Smith, D. (2001). Defect investigation of GaN thin films etched by photo-electrochemical and hot wet etching by atomic force and transmission electron microscopy. In Wide-Bandgap Electronics (pp. 162-167). (Materials Research Society Symposium Proceedings; Vol. 680). Materials Research Society. https://doi.org/10.1557/proc-680-e5.8