Polymer-Derived Si3N4/BN Composites

1989 ◽  
Vol 171 ◽  
Author(s):  
Wayde R. Schmidt ◽  
William J. Hurley ◽  
Vijay Sukumar ◽  
Robert H. Doremus ◽  
Leonard V. Interrante

ABSTRACTPartially crystalline silicon nitride, with a specific surface area greater than 200 m2/g, is obtained by the pyrolysis of an organometallic, polymeric precursor under NH3 to 1000 °C. Additional heating to 1400 °C under N2 produces alpha-Si3N4. The addition of up to 15% h-BN was found to affect the coarsening characteristics of amorphous silicon nitride by promoting surface area reduction and suppressing crystallinity. By combining Si3N4 and BN molecular and polymeric precursors prior to ceramic conversion, or incorporating Si, N, and B into a single preceramic polymer, the relative proportion and crystallinity of the ceramic phases can be controlled in the resulting Si3N4/BN composites.

1989 ◽  
Vol 4 (2) ◽  
pp. 394-398 ◽  
Author(s):  
V. S. Kaushik ◽  
A. K. Datye ◽  
D. L. Kendall ◽  
B. Martinez-Tovar ◽  
D. S. Simons ◽  
...  

Implantation of nitrogen at 150 KeV and a dose of 1 ⊠ 1018/cm2 into (110) silicon results in the formation of an amorphized layer at the mean ion range, and a deeper tail of nitrogen ions. Annealing studies show that the amorphized layer recrystallizes into a continuous polycrystalline Si3N4 layer after annealing for 1 h at 1200 °C. In contrast, the deeper nitrogen fraction forms discrete precipitates (located 1μm below the wafer surface) in less than 1 min at this temperature. The arcal density of these precipitates is 5 ⊠ 107/cm2 compared with a nuclei density of 1.6 ⊠ 105/cm2 in the amorphized layer at comparable annealing times. These data suggest that the nucleation step limits the recrystallization rate of amorphous silicon nitride to form continuous buried nitride layers. The nitrogen located within the damaged crystalline silicon lattice precipitates very rapidly, yielding semicoherent crystallites of β–Si3N4.


1991 ◽  
Vol 219 ◽  
Author(s):  
J. Kanicki ◽  
C. Godet ◽  
A. V. Gelatos

ABSTRACTThe effects of positive and negative bias stress on hydrogenated amorphous silicon nitride / crystalline silicon and hydrogenated amorphous silicon nitride / hydrogenated amorphous silicon (a-Si:H) structures are investigated as a function of stress time, stress temperature and stress bias. It is shown that in both structures bias stress induces a parallel shift of the C-V (capacitance-voltage) characteristics. For a given stress bias the direction of the C-V shift depends on the sign of the applied stress voltage, while the magnitude of the C-V shift depends on stress time and temperature. In addition, it is shown that positive bias stress slightly increases the number of localized states in the a-Si:H mobility gap, but negative bias stress does not. These results lead us to conclude that the C-V shift is not induced by dangling bond defects in a-Si:H but rather by carrier trapping in the insulator.


2019 ◽  
Vol 30 (25) ◽  
pp. 255601 ◽  
Author(s):  
M Biesuz ◽  
P Bettotti ◽  
S Signorini ◽  
M Bortolotti ◽  
R Campostrini ◽  
...  

1992 ◽  
Vol 7 (5) ◽  
pp. 1266-1270 ◽  
Author(s):  
Gian Domenico Sorarù ◽  
Alberto Ravagni ◽  
Roberto Dal Maschio ◽  
Giovanni Carturan ◽  
Florence Babonneau

A Zr-modified polycarbosilane has been obtained reacting a zirconium alkoxide with a polycarbosilane. This new preceramic polymer has been nitridated in flowing ammonia up to 1000 °C. The conversion process of the polymer precursor to the Si–N–Zr–O ceramic has been followed mainly by FT-IR, XRD, and TEM investigations. The formation of the Si–N–Si network starts at 600 °C. At 1000 °C the system can be described as an amorphous silicon nitride ceramic in which very fine zirconia-based particles are dispersed. Increasing the temperature to 1300 °C results in the crystallization of t-ZrO2 microcrystals (35 Å in size). At higher temperatures the crystallization of the silicon nitride matrix into β–Si3N4 has been observed.


2021 ◽  
Vol 5 (3) ◽  
Author(s):  
Jeffrey L. Braun ◽  
Sean W. King ◽  
Eric R. Hoglund ◽  
Mehrdad Abbasi Gharacheh ◽  
Ethan A. Scott ◽  
...  

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