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Low‐Pressure Chemical Vapor Deposition of α‐Si 3 N 4 from SiF 4 and NH 3 : Nucleation and Growth Characteristics
Author(s) -
Lee Woo Y.,
Strife James R.,
Veltri Richard D.
Publication year - 1992
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1992.tb05508.x
Subject(s) - crystallinity , crystallite , nucleation , amorphous solid , materials science , chemical vapor deposition , microstructure , deposition (geology) , atmospheric temperature range , mineralogy , coating , analytical chemistry (journal) , chemical engineering , crystallography , composite material , chemistry , metallurgy , nanotechnology , geology , paleontology , physics , organic chemistry , chromatography , sediment , meteorology , engineering
The crystal structure and surface morphology of Si 3 N 4 prepared by LPCVD were characterized as a function of processing conditions. Temperature was the most dominant variable which affected the coating microstructure. Strongly faceted crystalline Si 3 N 4 was deposited at temperatures above ∼ 1410°C. In the temperature range of 1300° to 1410°C, crystalline and amorphous phases were codeposited. The content of the crystalline phase rapidly decreased with decreased temperature. In this temperature range, the coating crystallinity was also influenced by kinetic factors such as deposition rate and reagent depletion. For example, Si 3 N 4 became more crystalline as the deposition rate was decreased by either decreasing the flow rate or increasing the NH 3 /SiF 4 molar ratio. At ∼ 1300°C, the coating surface appeared fully botryoidal, and the coatings were mostly amorphous. Changes in the orientation and size of Si 3 N 4 crystallites were parametrically documented. As the temperature was increased, the Si 3 N 4 grains generally became more preferentially oriented to the (102) and/or ( l 0 l ) where l = 1,2,3,., directions. The average facet size increased with coating thickness.