Atomic force microscopy study of sapphire surfaces annealed with a H 2O flux from a baffled molecular-beam epitaxy effusion cell loaded with Al(OH) 3

Michael M. Oye, Jeffrey B. Hurst, Davood Shahrjerdi, N. N. Kulkarni, A. Muller, A. L. Beck, R. Sidhu, C. K. Shih, Sanjay K. Banerjee, Joe C. Campbell, Archie L. Holmes, Terry J. Mattord, Jason M. Reifsnider

Research output: Contribution to journalArticlepeer-review

Abstract

We present an atomic force microscopy (AFM) study of sapphire surfaces that contain scratches with various severities. The objective was to observe the effects of substrate annealing at 850 °C for 200 min with a H2 O -based overpressure resulting from an Al (OH)3 powder that was thermally cracked at 1200 °C. The Al (OH)3 was decomposed into Al2 O3 and H2 O according to a partial Bayer process in a modified molecular-beam epitaxy (MBE) effusion cell, which was equipped with homemade baffles placed at its outlet. These homemade, simple-to-construct tantalum baffles allow for the selective outfluxing of gaseous species, from those that are solid based. A UTI 100C-model mass spectrometer was used to monitor the species present at the sapphire surface during annealing. Any aluminum-based solid species from the Al (OH)3 were not observed in the mass spectrum, although the H2 O -based species were. The sapphire substrates were annealed in a Varian Gen II MBE system, with H2 O beam equivalent pressures (BEPs) of 5× 10-6 and 2× 10-5 Torr, as well as with no H2 O flux at all. The AFM images show that the samples annealed with a higher H2 O BEP of 2× 10-5 Torr had noticeably less severe surface scratches than the samples that were annealed with lower H2 O BEPs.

Original languageEnglish (US)
Pages (from-to)1572-1576
Number of pages5
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Volume24
Issue number3
DOIs
StatePublished - May 2006

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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