TY - GEN
T1 - In-situ CARS detection of H2 in the CVD of Si3N4
AU - Hay, Stephen O.
AU - Veltri, R. D.
AU - Lee, W. Y.
AU - Roman, Ward C.
PY - 1991
Y1 - 1991
N2 - 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$/→Si3N4 + 12HF, in the CVD reactor under deposition conditions. Mass spectroscopic measurements, performed on the reactor exhaust, confirm that the primary gas phase species are N2, H2 and HF. H2 is observed spectroscopically both in the presence and absence of SiF4, and in a variety of precursor composition ratios.
AB - Silicon nitride (Si3N4) has been demonstrated to be an effective high- temperature anti-oxidant, especially when deposited in its α- crystalline form. UTRC has developed a pilot scale chemical vapor deposition (CVD) reactor capable of depositing α-Si3N4 from ammonia (NH 3) and silicon tetrafluoride (SiF4) at 1450 C. Coherent anti-Stokes Raman spectroscopy (CARS) has been applied to this reactor which has been fitted with line-of-sight optical access ports. Temperature and concentration measurements have been performed on gas phase species during the deposition of Si3N4. Based on the CARS detection of H2, the importance of high temperature surface (Si3N4) catalyzed decomposition of NH3: 2NH 3Δ→3H2 + N2, is established as a competing reaction to: 4NH3 + 3SiF4Δ$/→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.
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M3 - Conference contribution
AN - SCOPUS:0025849401
SN - 0819405256
T3 - Proceedings of SPIE - The International Society for Optical Engineering
SP - 352
EP - 358
BT - Proceedings of SPIE - The International Society for Optical Engineering
T2 - Optical Methods for Ultrasensitive Detection and Analysis: Techniques and Applications
Y2 - 21 January 1991 through 23 January 1991
ER -