Graduate Thesis Or Dissertation

 

Roles of gas and solid components in the direct nitridation of silicon Public Deposited

Downloadable Content

Download PDF
https://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/nc580q98r

Descriptions

Attribute NameValues
Creator
Abstract
  • The factors influencing the direct nitridation of silicon, including the effects of the native oxide layer covering the surface of silicon, the effects of hydrogen contained in the nitridation gas and the catalytic effects of metals added to the raw material silicon, were investigated, using a tubular flow reactor and a fluidized-bed reactor operated at temperatures ranging from 1150°C to 1390°C in a stream of nitrogen containing 10% hydrogen. The nitridation of silicon is not initiated until the native oxide is removed by an assistance of hydrogen contained in argon during the pretreatment or in the nitridation gas mixture. An induction period is observed before the initiation of the nitridation and depends on the nitridation temperature as well as the pretreatment time, which is associated with the removal of the oxide layer. The presence of hydrogen in the nitridation atmosphere is crucial for the nitridation of silicon. When pretreated silicon grains are exposed to nitrogen without hydrogen for a time period as short as 5 minutes, the subsequent nitridation, even with hydrogen, becomes extremely slow. The concentration of hydrogen as low as 0.3% is effective for sustaining the reactivity of silicon for the nitridation. The results suggest the formation of a protective layer on the surface of silicon when silicon grains are exposed to nitrogen without hydrogen. The protective film is suspected to be silicon oxynitride, or a mixture of silicon oxynitride and silicon dioxide or silicon nitride formed from the reaction of silicon with oxygen and nitrogen, depending on the temperature of its formation. However, the protective film does not form on the native oxide layer, and the reactivity of silicon is resumed upon the removal of the native oxide. An addition of calcium (as low as 0.125%) or yttrium (1.0-2.0%) to silicon suppresses the formation of β-silicon nitride while iron enhances the formation of silicon nitride. Copper promotes not only the nitridation but also the formation of α-silicon nitride at 1200°C, but enhances the β-phase formation at higher temperatures. The role of liquid phases on the formation of α-/β-silicon nitride was also discussed based on the nitridation of silicon impregnated with copper, calcium, silver, chromium and tungsten.
Resource Type
Date Available
Date Copyright
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Committee Member
Academic Affiliation
Non-Academic Affiliation
Subject
Rights Statement
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome, 256 Grayscale) using Capture Perfect 3.0.82 on a Canon DR-9080C in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces
Additional Information
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2012-07-26T19:42:03Z (GMT) No. of bitstreams: 1 PavajarnVarong2003.pdf: 7176843 bytes, checksum: 5efed81cb0a73cb36ed134a572a16269 (MD5)
  • description.provenance : Made available in DSpace on 2012-07-26T19:42:03Z (GMT). No. of bitstreams: 1 PavajarnVarong2003.pdf: 7176843 bytes, checksum: 5efed81cb0a73cb36ed134a572a16269 (MD5) Previous issue date: 2002-06-12
  • description.provenance : Submitted by Kevin Martin (martikev@onid.orst.edu) on 2012-07-11T17:31:52Z No. of bitstreams: 1 PavajarnVarong2003.pdf: 7176843 bytes, checksum: 5efed81cb0a73cb36ed134a572a16269 (MD5)
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2012-07-26T19:37:53Z (GMT) No. of bitstreams: 1 PavajarnVarong2003.pdf: 7176843 bytes, checksum: 5efed81cb0a73cb36ed134a572a16269 (MD5)

Relationships

Parents:

This work has no parents.

Items