In-situ CARS detection of H2 in the CVD of Si3N4

Stephen O. Hay, R. D. Veltri, W. Y. Lee, Ward C. Roman

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

2 Scopus citations

Abstract

Silicon nitride (Si3N4) has been demonstrated to be an effective high- temperature anti-oxidant, especially when deposited in its α- crystalline form. UTRC has developed a pilot scale chemical vapor deposition (CVD) reactor capable of depositing α-Si3N4 from ammonia (NH 3) and silicon tetrafluoride (SiF4) at 1450 C. Coherent anti-Stokes Raman spectroscopy (CARS) has been applied to this reactor which has been fitted with line-of-sight optical access ports. Temperature and concentration measurements have been performed on gas phase species during the deposition of Si3N4. Based on the CARS detection of H2, the importance of high temperature surface (Si3N4) catalyzed decomposition of NH3: 2NH 3Δ→3H2 + N2, is established as a competing reaction to: 4NH3 + 3SiF4Δ$/→Si3N4 + 12HF, in the CVD reactor under deposition conditions. Mass spectroscopic measurements, performed on the reactor exhaust, confirm that the primary gas phase species are N2, H2 and HF. H2 is observed spectroscopically both in the presence and absence of SiF4, and in a variety of precursor composition ratios.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
Pages352-358
Number of pages7
StatePublished - 1991
EventOptical Methods for Ultrasensitive Detection and Analysis: Techniques and Applications - Los Angeles, CA, USA
Duration: 21 Jan 199123 Jan 1991

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume1435
ISSN (Print)0277-786X

Conference

ConferenceOptical Methods for Ultrasensitive Detection and Analysis: Techniques and Applications
CityLos Angeles, CA, USA
Period21/01/9123/01/91

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