Diborane B2H6 is a conventional precursor for the CVD deposition of boron-containing films [1] It is largely used as a p-type dopant in the deposition of epitaxial and amorphous silicon thin films as well as in compound semiconductor industry. [44]
B2H6 has been demonstrated to produce stoichiometric boron nitride films by CVD process at 400°C with large excess hydrazine N2H4 as nitrogen source[569]
Boron nanoparticles have been obtained by thermolysis of diborane B2H6 at temperatures 700°C- 2250°C, but the size distribution produced was broad or the particles were extensively aggregated.[[i],[ii],[iii]]
B2H6 for B and BPx layers by CVD
Thin films of boron B and boron phosphide BPx have been grown using diborane as boron precursor (and PH3 + H2 as co-reactants) on Si(100) substrates at 600–1000°C, by thermnal CVD as well as by UV-assisted (deuterium lamp) CVD. I t has been determined that the activation energies for film growth decreased by using the deuterium lamp, allowing to grow BP films at low growth temperature (by ~100°C) compared to thermal CVD. [[i]]
[i] Y Kumashiro, K Sato, S Chiba, S Yamada, D Tanaka, K Hyodo, T Yokoyama, K Hirata
Journal of Solid State Chemistry, Volume 154, Issue 1, October 2000, Pages 39-44, “Preparation of Boron and Boron Phosphide Films by Photo- and Thermal Chemical Vapor Deposition Processes”
[i] J. D. Casey, J. S. Haggerty, J. Mater. Sci., 1987, 22, 737–744.
[ii] H. L. Johnston, H. N. Hersh, E. C. Kerr, J. Am. Chem. Soc., 1951, 73, 1112–1117
[iii] P. Z. Si, M. Zhang, C. Y. You, D. Y. Geng, J. H. Du, X. G. Zhao, X. L. Ma and Z. D. Zhang, J. Mater. Sci., 2003, 38, 689–692
Decaborane (decaboron tetradecahydride) B10H14
Decaborane B10H14 was used for the deposition of boron nanoparticles by CVD. Passage of decaborane vapour in an Ar carrier at 1 atm through a hot zone at 700–900°C affords a grey-brown, non-pyrophoric powder. The powder consists of 97% boron and is free of hydrogen as judged by combustion analysis.