Tin tetraalkyls is the important class of Sn CVD precursors.
Synthesis:
SnCl4 + 4 LiR/BrMgR/NaR → SnR4 + 4 LiCl/”BrMgCl”/NaCl
3 SnCl4 + 4 AlR3 → 3 SnR4 + 4 AlCl3
More complex tetraalkylstannanes can be synthesised by hydrostannylation reaction: R3SnH + R´CH=CH2 → R3SnCH2CH2R`
Deposition:
Sn(IV) compounds undergo facile ligand redistribution reactions which will
lead to the deposition of Sn. As example the decomposition of EtSnH3 is
shown below:
2 EtSnH3 → SnH4 + Et2SnH2
DT + Ph3SnH → SnPh4 + Sn2Ph6 + Sn + PhH
[The Chemistry of Metal CVD, International Research Training Group, “Materials and Concepts for Advanced Interconnects”, Prof. Dr. Heinrich Lang]
Tetramethyltin SnMe4 has been applied a precursor for the Sn-doping of CdO films grown by the atmospheric pressure MOCVD. [4]
Sn-Ni intermetallic particles were prepared by a process involving CVD of SnMe4 onto Ni/SiO2 substrates [4]
Metallic tin films have been obtained by low pressure decomposition of tetramethyltin SnMe4 at 500-600°C. [1, 564]
Tetraethyltin SnEt4 has been applied as MOCVD precursor for the growth of SnO2 thin films on glass and Ge substrates, using O2 as oxidant, at low pressure 10 mTorr (2.5mTorr SnEt4, 7.5mTorr O2). Films were 2.8μm thick and contained ~15% of carbon, according to SEM and EDX. [565]
Tetraethyltin SnEt4 has been studied as precursor for the preparation of SnO2 thin films by ALD, for the applications such as solid state gas sensors, solar cells,
transparent conductive oxide coatings, catalysts, and anodes for Li-ion batteries. As co-reactants for SnOx deposition were studied H2O, H2O2, O2, O3, and O2 plasma. The type of co-reactant had a huge impact on the growth rate, composition and morphology of
the films. [[i]]
[i] D. V. Nazarov ; M.Yu. Maximov ; P.A. Novikov; Anatoly A. Popovich; V.M. Smirnov , International Baltic Conference on Atomic Layer Deposition (BALD), 2-4 Oct. 2016 , DOI: 10.1109/BALD.2016.7886523 , « Atomic layer deposition of tin oxide nanofilms using tetraethyltin »