Journal of Electronic Materials

, Volume 39, Issue 10, pp 2237–2242

In Situ Raman Analysis of a Bulk GaN-Based Schottky Rectifier Under Operation

Authors

  • Hui Xu
    • Department of PhysicsAuburn University
  • Siddharth Alur
    • Department of PhysicsAuburn University
  • Yaqi Wang
    • Department of PhysicsAuburn University
  • An-Jen Cheng
    • Department of PhysicsAuburn University
  • Kilho Kang
    • Department of PhysicsAuburn University
  • Yogeshkumar Sharma
    • Department of PhysicsAuburn University
    • Department of PhysicsAuburn University
  • Claude Ahyi
    • Department of PhysicsAuburn University
  • John Williams
    • Department of PhysicsAuburn University
  • Chaokang Gu
    • Department of Chemistry and BiochemistryAuburn University
  • Andrew Hanser
    • Kyma Technologies, Inc.
  • Tanya Paskova
    • Kyma Technologies, Inc.
  • Edward A. Preble
    • Kyma Technologies, Inc.
  • Keith R. Evans
    • Kyma Technologies, Inc.
  • Yi Zhou
    • Department of Electrical EngineeringUniversity of California
Article

DOI: 10.1007/s11664-010-1304-3

Cite this article as:
Xu, H., Alur, S., Wang, Y. et al. Journal of Elec Materi (2010) 39: 2237. doi:10.1007/s11664-010-1304-3

We have fabricated vertical Schottky rectifiers based on a free-standing GaN substrate and have measured the temperature of the device under operation in situ using micro-Raman spectroscopy. The n-type bulk GaN wafer with 500 μm thickness was prepared using hydride vapor-phase epitaxy. The carrier concentration of the wafer was ~2.4 × 1016 cm−3. Semitransparent Ni and multilayered Ti/Al/Pt/Au were used to make a Schottky and a full backside ohmic contact, respectively. In this investigation, Raman spectra were collected as a function of the forward power applied to the Schottky diode. A systematic shift and broadening of the Raman E2 peak were observed as a function of increasing bias. This was caused by device heating due to the increase in current as the forward bias was increased. It was demonstrated that micro-Raman spectroscopy can serve as an excellent in situ diagnostic tool for analyzing thermal characteristics of the GaN Schottky diode. Moreover, the strain caused by the piezoelectric effect was calculated to lead to a shift of the Raman peak at the level of 0.001 cm−1. This confirmed that the observed Raman peak shift was predominantly produced by a thermal not piezoelectric effect.

Keywords

GaNSchottky rectifierRaman spectroscopy

Copyright information

© TMS 2010