Structural defects responsible for excessive leakage current in Schottky diodes prepared on undoped n-GaN films grown by hydride vapor phase epitaxy

Alexander Y. Polyakov, Eugene B. Yakimov, Nikolai B. Smirnov, Anatoliy V. Govorkov, Alexander S. Usikov, Heikki Helava, Yuri N. Makarov, In-Hwan Lee

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Schottky diodes fabricated on undoped n-GaN films grown by hydride vapor phase epitaxy showed more than two orders of magnitude higher reverse current if the films contained open core defects. The open core defects were revealed by scanning electron microscope observation in secondary electrons, microcathodoluminescence (MCL), and electron beam induced current (EBIC) modes. Plan-view EBIC imaging showed that such films contained a relatively high density of large (∼10 μm in diameter) dark defects that were absent in good films with low leakage current. In plan-view scanning electron microscope images, pits with the density similar to the density of dark defects were observed. Cross-sectional MCL observation showed that the pits terminated the vertical micropipes starting near the interface with the substrate. Some of the micropipes closed approximately halfway through the grown thickness. The regions of micropipes, either closed or not, showed a higher intensity of bandedge and defect MCL bands. Possible reasons for the formation of such structures are discussed.

Original languageEnglish
Article number051212
JournalJournal of Vacuum Science and Technology B:Nanotechnology and Microelectronics
Volume32
Issue number5
DOIs
Publication statusPublished - 2014 Sep 1
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering
  • Materials Chemistry

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