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Formation of Reaction‐Bonded Silicon Nitride from Silane‐Derived Silicon Powders: Nucleation and Growth Mechanisms
Author(s) -
Sheldon Brian W,
Rankin Janet,
Haggerty John S.
Publication year - 1995
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.1151-2916.1995.tb08861.x
Subject(s) - nucleation , materials science , silane , silicon , silicon nitride , evaporation , transmission electron microscopy , analytical chemistry (journal) , vaporization , chemical engineering , thermogravimetric analysis , nitride , layer (electronics) , nanotechnology , chemistry , metallurgy , composite material , organic chemistry , physics , engineering , thermodynamics
The nucleation and growth of Si 3 N 4 on silane‐derived Si powders was investigated with transmission electron microscopy and FTIR spectroscopy. Thermogravimetric analysis (TGA) was also used to monitor the process through different stages of the reaction. The FTIR and TEM results provide clear evidence that the nucleation of crystalline Si 3 N 4 coincides with the onset of rapid nitridation. Electron diffraction indicates that Si 3 N 4 forms heteroepitaxially on the Si powder surfaces, with Si (111) || Si 3 N 4 (0001) and Si || Si 3 N 4 . Also, flat interfaces between the Si and Si 3 N 4 (compared to the initial spherical surface of the Si powders) indicate that a significant rearrangement of the particle surface occurs during the initial stages of nitridation. The results reported here demonstrate that the rapid, low‐temperature nitridation observed with silane‐derived powders is possible because the Si/vapor surfaces are not covered with a continuous Si 3 N 4 product layer. The measured nitridation rates are comparable to Si evaporation rates, which suggests that Si vaporization is rate limiting. This is significantly different from conventional RBSN, where nitridation is limited by solid‐state diffusion through a Si 3 N 4 product layer.