Cleaning of GaN surfaces

L. L. Smith, S. W. King, R. J. Nemanich, R. F. Davis

Research output: Contribution to journalArticle

106 Scopus citations

Abstract

The work described in this paper is part of a systematic study of surface cleaning and ohmic contact strategies for GaN. The goal of this investigation was to determine the most effective methods of wet chemical and thermal desorption cleaning for the removal of oxygen (O) and carbon (C) prior to metallization. Hydrochloric (HCl) and hydrofluoric (HF) acid-based cleaning treatments were compared, and thermal desorption as a function of temperature was characterized by sequential heating under ultra high vacuum (UHV) conditions. Auger electron spectroscopy (AES) analysis was used to monitor the presence of surface O and C throughout the study. For the removal of surface oxide, HCl-based solutions were found to be most effective; under as-cleaned, air-exposed conditions, HCl:DI H2O (1:1) solution resulted in the lowest levels of residual O and C. However, HF-based solutions resulted in more effective thermal desorption of C from the surfaces. In contrast to the results typically observed in the thermal desorption cleaning of GaAs, complete removal of oxygen and carbon from airexposed GaN surfaces was not seen using vacuum heating alone, even to temperatures where GaN decomposition occurs (>800-900°C). The results of this study indicate that the presence of oxygen and carbon on the GaN surface is persistent even to high temperatures, and that further in-situ cleaning methods must be added to obtain spectroscopically clean GaN surfaces.

Original languageEnglish (US)
Pages (from-to)805-810
Number of pages6
JournalJournal of Electronic Materials
Volume25
Issue number5
DOIs
StatePublished - May 1996

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Keywords

  • Auger electron spectroscopy (AES)
  • Gallium nitride
  • Metallization
  • Ohmic contacts
  • Surface analysis
  • Surface cleaning
  • Thermal desorption

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry

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