Thermal healing of the sub-surface damage layer in sapphire

Malki Pinkas, Haim Lotem, Yuval Golan, Yeheskel Einav, Roxana Golan, Elad Chakotay, Avivit Haim, Ela Sinai, Moshe Vaknin, Yasmin Hershkovitz, Atara Horowitz

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


The sub-surface damage layer formed by mechanical polishing of sapphire is known to reduce the mechanical strength of the processed sapphire and to degrade the performance of sapphire based components. Thermal annealing is one of the methods to eliminate the sub-surface damage layer. This study focuses on the mechanism of thermal healing by studying its effect on surface topography of a- and c-plane surfaces, on the residual stresses in surface layers and on the thickness of the sub-surface damage layer. An atomically flat surface was developed on thermally annealed c-plane surfaces while a faceted roof-top topography was formed on a-plane surfaces. The annealing resulted in an improved crystallographic perfection close to the sample surface as was indicated by a noticeable decrease in X-ray rocking curve peak width. Etching experiments and surface roughness measurements using white light interferometry with sub-nanometer resolution on specimens annealed to different extents indicate that the sub-surface damage layer of the optically polished sapphire is less than 3 μm thick and it is totally healed after thermal treatment at 1450 °C for 72 h.

Original languageEnglish
Pages (from-to)323-329
Number of pages7
JournalMaterials Chemistry and Physics
Issue number1
StatePublished - 1 Nov 2010


  • AFM
  • Etching
  • H PO
  • Light interferometry
  • Mechanical properties
  • Sapphire
  • Strength
  • Thermal Annealing
  • X-ray rocking curve

ASJC Scopus subject areas

  • Materials Science (all)
  • Condensed Matter Physics


Dive into the research topics of 'Thermal healing of the sub-surface damage layer in sapphire'. Together they form a unique fingerprint.

Cite this